File: library.html

package info (click to toggle)
funtools 1.4.8-2
links: PTS, VCS
area: main
in suites: forky, sid
size: 15,004 kB
sloc: ansic: 89,502; sh: 10,714; lex: 4,613; asm: 3,281; ada: 1,681; makefile: 1,468; pascal: 1,089; cpp: 1,001; cs: 879; perl: 161; python: 119; yacc: 64; sed: 38; csh: 10; tcl: 9
file content (2823 lines) | stat: -rw-r--r-- 114,779 bytes
parent folder | download | duplicates (7)
<!-- =defdoc funlib funlib 3 -->
<HTML>
<HEAD>
<TITLE>Funtools Programming</TITLE>
</HEAD>
<BODY>

<!-- =section funlib NAME -->
<H2><A NAME="funlib">FunLib: the Funtools Programming Interface</A></H2>

<!-- =section funlib SYNOPSIS -->
<H2>Summary</H2>
A description of the Funtools library.

<!-- =section funlib DESCRIPTION -->
<H2><A NAME="intro">Introduction to the Funtools Programming Interface</H2></A>
<P>
To create a Funtools application, you need to include
the funtools.h definitions file in your code:
<PRE>
  #include &lt;funtools.h&gt;
</PRE>

You then call Funtools subroutines and functions to access Funtools data.
The most important routines are:
<UL>

<P>
<LI> <A HREF="./library.html#funopen">FunOpen</A>: open a Funtools file
<LI><A HREF="./library.html#funinfoget">FunInfoGet</A>: get info about an image or table
<LI><A HREF="./library.html#funimageget">FunImageGet</A>: retrieve image data
<LI><A HREF="./library.html#funimagerowget">FunImageRowGet</A>: retrieve image data by row
<LI><A HREF="./library.html#funimageput">FunImagePut</A>: output image data
<LI><A HREF="./library.html#funimagerowput">FunImageRowPut</A>: output image data by row
<LI><A HREF="./library.html#funcolumnselect">FunColumnSelect</A>: select columns in a table for access
<LI><A HREF="./library.html#funtablerowget">FunTableRowGet</A>: retrieve rows from a table
<LI><A HREF="./library.html#funtablerowput">FunTableRowPut</A>: output rows to a table
<LI> <A HREF="./library.html#funclose">FunClose</A>: close a Funtools file
</UL>

Your program must be linked against the libfuntools.a library,
along with the math library. The following libraries also might be required
on your system:
<UL>
<LI> -lsocket -lnsl for socket support
<LI> -ldl           for dynamic loading
</UL>
<P>
For example, on a Solaris system using gcc, use the following link line:
<PRE>
  gcc -o foo foo.c -lfuntools -lsocket -lnsl -ldl -lm
</PRE>
On a Solaris system using Solaris cc, use the following link line:
<PRE>
  gcc -o foo foo.c -lfuntools -lsocket -lnsl -lm
</PRE>
On a Linux system using gcc, use the following link line:
<PRE>
  gcc -o foo foo.c -lfuntools -ldl -lm
</PRE>
Once configure has built a Makefile on your platform, the required
"extra" libraries (aside from -lm, which always is required) are
specified in that file's EXTRA_LIBS variable. For example, under
Linux you will find:
<PRE>
  grep EXTRA_LIBS Makefile
  EXTRA_LIBS      =  -ldl
  ...
</PRE>

<P>
The Funtools library contains both the zlib library
(http://www.gzip.org/zlib/) and Doug Mink's WCS library
(http://tdc-www.harvard.edu/software/wcstools/).  It is not necessary
to put these libraries on a Funtools link line. Include files
necessary for using these libraries are installed in the Funtools
include directory.

<H2><A NAME="tutorial">Funtools Programming Tutorial</A></H2>

The
<A HREF="./library.html#funopen">FunOpen()</A>
function is used to open a FITS file, an array, or a raw event file:
<PRE>
  /* open the input FITS file for reading */
  ifun = FunOpen(iname, "r", NULL);
  /* open the output FITS file for writing, and connect it to the input file */
  ofun = FunOpen(iname, "w", ifun);
</PRE>
A new output file can inherit header parameters automatically from
existing input file by passing the input Funtools handle as the last
argument to the new file's
<A HREF="./library.html#funopen">FunOpen()</A>
call as shown above.

<P>
For image data, you then can call
<A HREF="./library.html#funimageget">FunImageGet()</A>
to read an image into memory.
<PRE>
  float buf=NULL;
  /* extract and bin the data section into an image buffer */
  buf = FunImageGet(fun, NULL, "bitpix=-32");
</PRE>
If the (second) buf argument to this call is NULL, buffer space is allocated
automatically. The (third) plist argument can be used to specify the
return data type of the array.  If NULL is specified, the data type of
the input file is used.

<P>
To process an image buffer, you would generally make a call to 
<A HREF="./library.html#funinfoget">FunInfoGet()</A> to determine the
dimensions of the image (which may have been changed from the original
file dimensions due to <A HREF="./files.html#sections">Funtools image
sectioning</A> on the command line). In a FITS image, the index along
the dim1 axis varies most rapidly, followed by the dim2 axis, etc.
Thus, to access each pixel in an 2D image, use a double loop such as:
</PRE>
  buf = FunImageGet(fun, NULL, "bitpix=-32");
  FunInfoGet(fun, FUN_SECT_DIM1, &dim1, FUN_SECT_DIM2, &dim2, 0);
  for(i=1; i<=dim2; i++){
    for(j=1; j<=dim1; j++){
      ... process buf[((i-1)*dim1)+(j-1)] ...
    }
  }
</PRE>
or:
<PRE>
  buf = FunImageGet(fun, NULL, "bitpix=-32");
  FunInfoGet(fun, FUN_SECT_DIM1, &dim1, FUN_SECT_DIM2, &dim2, 0);
  for(i=0; i&lt;(dim1*dim2); i++){
    ... process buf[i] ...
  }
</PRE>
Finally, you can write the resulting image to disk using
<A HREF="./library.html#funimageput">FunImagePut()</A>:
<PRE>
  FunImagePut(fun2, buf, dim1, dim2, -32, NULL);
</PRE>
Note that Funtools automatically takes care of book-keeping tasks such as
reading and writing FITS headers (although you can, of course, write
your own header or add your own parameters to a header).

<P>
For binary tables and raw event files, a call to
<A HREF="./library.html#funopen">FunOpen()</A>
will be followed by a call to the
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>
routine to select columns to be read from the input file and/or
written to the output file:

<PRE>
  typedef struct evstruct{
    double time;
    int time2;
  } *Ev, EvRec;
  FunColumnSelect(fun, sizeof(EvRec), NULL,
                  "time",      "D",     "rw",  FUN_OFFSET(Ev, time),
                  "time2",     "J",     "w",   FUN_OFFSET(Ev, time2),
                  NULL);
</PRE>
Columns whose (third) mode argument contains an "r" are "readable",
i.e., columns will be read from the input file and converted into the
data type specified in the call's second argument. These columns
values then are stored in the specified offset of the user record
structure.  Columns whose mode argument contains a "w" are
"writable", i.e., these values will be written to the output file.
The
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>
routine also offers the option of automatically merging user
columns with the original input columns when writing the output
rows.

<P>
Once a set of columns has been specified, you can retrieve rows using
<A HREF="./library.html#funtablerowget">FunTableRowGet()</A>,
and write the rows using
<A HREF="./library.html#funtablerowput">FunTableRowPut()</A>:
<PRE>
  Ev ebuf, ev;
  /* get rows -- let routine allocate the array */
  while( (ebuf = (Ev)FunTableRowGet(fun, NULL, MAXROW, NULL, &got)) ){
    /* process all rows */
    for(i=0; i&lt;got; i++){
      /* point to the i'th row */
      ev = ebuf+i;
      /* time2 is generated here */
      ev->time2 = (int)(ev->time+.5);
      /* change the input time as well */
      ev->time = -(ev->time/10.0);
    }
    /* write out this batch of rows with the new column */
    FunTableRowPut(fun2, (char *)ebuf, got, 0, NULL);
    /* free row data */
    if( ebuf ) free(ebuf);
  }
</PRE>
The input rows are retrieved into an array of user structs, which
can be accessed serially as shown above. Once again, Funtools
automatically takes care of book-keeping tasks such as reading and writing
FITS headers (although you can, of course, write your own header or
add your own parameters to a header).

<P>
When all processing is done, you can call
<A HREF="./library.html#funclose">FunClose()</A>
to close the file(s):
<PRE>
  FunClose(fun2);
  FunClose(fun);
</PRE>

<P>
These are the basics of processing FITS files (and arrays or raw event
data) using Funtools. The routines in these examples are described in
more detail below, along with a few other routines that support
parameter access, data flushing, etc.

<H2><A NAME="compiling">Compiling and Linking</A></H2>
<P>
To create a Funtools application, a software developer will include
the funtools.h definitions file in Funtools code:
<PRE>
  #include &lt;funtools.h&gt;
</PRE>
The program is linked against the libfuntools.a library, along with the
math library (and the dynamic load library, if the latter is available
on your system):
<PRE>
  gcc -o foo foo.c -lfuntools -ldl -lm
</PRE>
<P>
If gcc is used, Funtools filtering can be performed using dynamically
loaded shared objects that are built at run-time. Otherwise, filtering
is performed using a slave process.
<P>
Funtools has been built on the following systems:
<UL>
<LI> Sun/Solaris 5.X
<LI> Linux/RedHat Linux 5.X,6.X,7.X
<LI> Dec Alpha/OSF1 V4.X
<LI> WindowsNT/Cygwin 1.0
<LI> SGI/IRIX64 6.5
</UL>

<H2><A NAME="order">A Short Digression on Subroutine Order</A></H2>
<P>
There is a natural order for all I/O access libraries. You would not
think of reading a file without first opening it, or writing a file
after closing it. A large part of the experiment in funtools is to use
the idea of "natural order" as a means of making programming
easier. We do this by maintaining the state of processing for a given
funtools file, so that we can do things like write headers and flush
extension padding at the right time, without you having to do it.

<P>
For example, if you open a new funtools file for writing using
<A HREF="./library.html#funopen">FunOpen()</A>,
then generate an array of image data and call
<A HREF="./library.html#funimageput">FunImagePut()</A>,
funtools knows to write the image header automatically.
There is no need to think about writing a standard header.
Of course, you can add parameters to the file first by
calling one of the
<A HREF="./library.html#funparamput">FunParamPut()</A>
routines, and these parameters will automatically be added
to the header when it is written out.  There still is no
need to write the header explicitly.

<P>
Maintaining state in this way means that there are certain rules of
order which should be maintained in any funtools program. In particular,
we strongly recommend the following ordering rules be adhered to:

<UL>
<LI> When specifying that input extensions be copied to an output file
via a reference handle, open the output file <B>before</B> reading the
input file. (Otherwise the initial copy will not occur).

<LI> Always write parameters to an output file using one of the
<A HREF="./library.html#funparamput">FunParamPut()</A> calls
<B>before</B> writing any data. (This is a good idea for all FITS
libraries, to avoid having to recopy data is the FITS header needs
to be extended by adding a single parameter.)

<LI> If you retrieve an image, and need to know the data
type, use the FUN_SECT_BITPIX option of
<A HREF="./library.html#funinfoget">FunInfoGet()</A>,
<B>after</B> calling
<A HREF="./library.html#funimageget">FunImageGet()</A>, since
it is possible to change the value of BITPIX from the latter.

<LI> When specifying that input extensions be copied to an output file
via a reference handle, close the output file <B>before</B> closing
input file, or else use
<A HREF="./library.html#funflush">FunFlush()</A>
explicitly on the output file
<B>before</B> closing the input file. (Otherwise the final copy will
not occur).
</UL>

<P>
We believe that these are the natural rules that are implied in most
FITS programming tasks. However, we recognize that making explicit use
of "natural order" to decide what automatic action to take on behalf
of the programmer is experimental.  Therefore, if you find that your
needs are not compatible with our preferred order, please let us know
-- it will be most illuminating for us as we evaluate this experiment.

<H2><A NAME="examples">Funtools Programming Examples</A></H2>
<P>
The following complete coding examples are provided to illustrate the
simplicity of Funtools applications.  They can be found in the funtest
subdirectory of the Funtools distribution.  In many cases, you should
be able to modify one of these programs to generate your own Funtools
program:
<UL>
<LI><A HREF="./evread.c">evread.c</A>: read and write binary tables
<LI><A HREF="./evcol.c">evcols.c</A>: add column and rows to binary tables
<LI><A HREF="./evmerge.c">evmerge.c</A>: merge new columns with existing columns
<LI><A HREF="./evnext.c">evnext.c</A>: manipulate raw data pointers
<LI><A HREF="./imblank.c">imblank.c</A>: blank out image values below a threshold
<LI><A HREF="./asc2fits.c">asc2fits.c</A>: convert a specific ASCII table to FITS binary table
</UL>

<H2><A NAME="reference">The Funtools Programming Reference Manual</A></H2>
<P>
<PRE>
#include &lt;funtools.h&gt;

Fun <A HREF="./library.html#funopen">FunOpen(char *name, char *mode, Fun ref)</A>

void *<A HREF="./library.html#funimageget">FunImageGet(Fun fun, void *buf, char *plist)</A>

int <A HREF="./library.html#funimageput">FunImagePut(Fun fun, void *buf, int dim1, int dim2, int bitpix, char *plist)</A>

void * <A HREF="./library.html#funimagerowget">FunImageRowGet(Fun fun, void *buf, int rstart, int rstop, char *plist)</A>

void * <A HREF="./library.html#funimagerowput">FunImageRowPut(Fun fun, void *buf, int rstart, int rstop, int dim1, int dim2, int bitpix, char *plist)</A>

int <A HREF="./library.html#funcolumnselect">FunColumnSelect(Fun fun, int size, char *plist, ...)</A>

void <A HREF="./library.html#funcolumnactivate">FunColumnActivate(Fun fun, char *s, char *plist)</A>

int <A HREF="./library.html#funcolumnlookup">FunColumnLookup(Fun fun, char *s, int which, char **name, int *type, int *mode, int *offset, int *n, int *width)</A>

void *<A HREF="./library.html#funtablerowget">FunTableRowGet(Fun fun, void *rows, int maxrow, char *plist, int *nrow)</A>

int <A HREF="./library.html#funtablerowput">FunTableRowPut(Fun fun, void *rows, int nev, int idx, char *plist)</A>

int <A HREF="./library.html#funparamget">FunParamGetb(Fun fun, char *name, int n, int defval, int *got)</A>

int <A HREF="./library.html#funparamget">FunParamGeti(Fun fun, char *name, int n, int defval, int *got)</A>

double <A HREF="./library.html#funparamget">FunParamGetd(Fun fun, char *name, int n, double defval, int *got)</A>

char *<A HREF="./library.html#funparamget">FunParamGets(Fun fun, char *name, int n, char *defval, int *got)</A>

int <A HREF="./library.html#funparamput">FunParamPutb(Fun fun, char *name, int n, int value, char *comm, int append)</A>

int <A HREF="./library.html#funparamput">FunParamPuti(Fun fun, char *name, int n, int value, char *comm, int append)</A>

int <A HREF="./library.html#funparamput">FunParamPutd(Fun fun, char *name, int n, double value, int prec, char *comm, int append)</A>

int <A HREF="./library.html#funparamput">FunParamPuts(Fun fun, char *name, int n, char *value, char *comm, int append)</A>

int <A HREF="./library.html#funinfoget">FunInfoGet(Fun fun, int type, ...)</A>

int <A HREF="./library.html#funinfoput">FunInfoPut(Fun fun, int type, ...)</A>

void <A HREF="./library.html#funflush">FunFlush(Fun fun, char *plist)</A>

void <A HREF="./library.html#funclose">FunClose(Fun fun)</A>
</PRE>

<!-- =defdoc funopen funopen 3 -->

<!-- =section funopen NAME -->
<H2><A NAME="funopen">FunOpen - open a Funtools data file</A></H2>

<!-- =section funopen SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  Fun FunOpen(char *name, char *mode, Fun ref);
</PRE>
</B>

<!-- =section funopen DESCRIPTION -->
<P>
The <B>FunOpen()</B> routine opens a Funtools data file for reading or
appending, or creates a new FITS file for writing. The <B>name</B>
argument specifies the name of the Funtools data file to open. You can
use IRAF-style bracket notation to specify
<A HREF="./files.html">Funtools Files, Extensions, and Filters</A>.
A separate call should be made each time a different FITS extension is
accessed:
<PRE>
  Fun fun;
  char *iname;
  ...
  if( !(fun = FunOpen(iname, "r", NULL)) ){
    fprintf(stderr, "could not FunOpen input file: %s\n", iname);
    exit(1);
  }
</PRE>
<P>
If <B>mode</B> is "r", the file is opened for reading, and processing
is set up to begin at the specified extension. For reading,
<B>name</B> can be <B>stdin</B>, in which case the standard input is read.

<P>
If <B>mode</B> is "w", the file is created if it does not exist, or
opened and truncated for writing if it does exist. Processing starts
at the beginning of the file.  The <B>name</B> can be <B>stdout</B>,
in which case the standard output is readied for processing.

<P>
If <B>mode</B> is "a", the file is created if it does not exist, or
opened if it does exist. Processing starts at the end of the file.
The <B>name</B> can be <B>stdout</B>, in which case the standard
output is readied for processing.

<P>
When a Funtools file is opened for writing or appending, a previously
opened <A HREF="./library.html#refhandle">Funtools reference
handle</A> can be specified as the third argument. This handle
typically is associated with the input Funtools file that will be used
to generate the data for the output data.  When a reference file is
specified in this way, the output file will inherit the (extension)
header parameters from the input file:
<PRE>
  Fun fun, fun2;
  ...
  /* open input file */
  if( !(fun = FunOpen(argv[1], "r", NULL)) )
    gerror(stderr, "could not FunOpen input file: %s\n", argv[1]);
  /* open the output FITS image, inheriting params from input */
  if( !(fun2 = FunOpen(argv[2], "w", fun)) )
    gerror(stderr, "could not FunOpen output file: %s\n", argv[2]);
</PRE>
Thus, in the above example, the output FITS binary table file will
inherit all of the parameters associated with the input binary table
extension.
<P>
A file opened for writing with a 
<A HREF="./library.html#refhandle">Funtools reference handle</A> also
inherits the selected columns (i.e. those columns chosen for
processing using the 
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A> routine)
from the reference file as its default columns. This makes it easy to
open an output file in such a way that the columns written to the
output file are the same as the columns read in the input file. Of
course, column selection can easily be tailored using the 
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A> routine.
In particular, it is easy to merge user-defined columns with the input
columns to generate a new file.  See the 
<A HREF="./evmerge.c">evmerge</A> for a complete example.

<P>
In addition, when a
<A HREF="./library.html#refhandle">Funtools reference handle</A>
is supplied in a <A HREF="./library.html#funopen">FunOpen()</A> call,
it is possible also to specify that all other extensions from the
reference file (other than the input extension being processed) should
be copied from the reference file to the output file. This is useful,
for example, in a case where you are processing a FITS binary table 
or image and you want to copy all of the other extensions to
the output file as well.  Copy of other extensions is controlled by
adding a "C" or "c" to the mode string of the 
<A HREF="./library.html#funopen">FunOpen()</A> call <B>of the input
reference file</B>.  If "C" is specified, then other extensions are
<B>always</B> copied (i.e., copy is forced by the application).  If
"c" is used, then other extensions are copied if the user requests
copying by adding a plus sign "+" to the extension name in the bracket
specification.  For example, the <B>funtable</B> program utilizes
"c" mode, giving users the option of copying all other extensions:
<PRE>
  /* open input file -- allow user copy of other extensions */
  if( !(fun = FunOpen(argv[1], "rc", NULL)) )
    gerror(stderr, "could not FunOpen input file: %s\n", argv[1]);
  /* open the output FITS image, inheriting params from input */
  if( !(fun2 = FunOpen(argv[2], "w", fun)) )
    gerror(stderr, "could not FunOpen output file: %s\n", argv[2]);
</PRE>

Thus, <B>funtable</B> supports either of these command lines:
<PRE>
  # copy only the EVENTS extension
  csh> funtable "test.ev[EVENTS,circle(512,512,10)]" foo.ev
  # copy ALL extensions
  csh> funtable "test.ev[EVENTS+,circle(512,512,10)]" foo.ev
</PRE>

<P>
Use of a <A HREF="./library.html#refhandle">Funtools reference
handle</A> implies that the input file is opened before the output
file.  However, it is important to note that if copy mode ("c" or "C")
is specified for the input file, the actual input file open is delayed
until just after the output file is opened, since the copy of prior
extensions to the output file takes place while Funtools is seeking to
the specified input extension.  This implies that the output file
should be opened before any I/O is done on the input file or else the
copy will fail.  Note also that the copy of subsequent extension will
be handled automatically by
<A HREF="./library.html#funclose">FunClose()</A>
if the output file is
closed before the input file. Alternatively, it can be done explicitly
by <A HREF="./library.html#funflush">FunFlush()</A>, but again, this
assumes that the input file still is open.

<P>
Upon success <A HREF="./library.html#funopen">FunOpen()</A> returns a
Fun handle that is used in subsequent Funtools calls. On error, NULL
is returned.

<!-- =defdoc funimageget funimageget 3 -->

<!-- =section funimageget NAME -->
<H2><A NAME="funimageget">FunImageGet - get an image or image section</A></H2>

<!-- =section funimageget SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  void *FunImageGet(Fun fun, void *buf, char *plist)
</PRE>
</B>

<!-- =section funimageget DESCRIPTION -->
<P>
The <B>FunImageGet()</B> routine returns an binned image array of the
specified section of a Funtools data file.  If the input data are
already of type image, the array is generated by extracting the
specified image section and then binning it according to the specified
bin factor.  If the input data are contained in a binary table or raw
event file, the rows are binned on the columns specified by the
<B>bincols=</B> keyword (using appropriate default columns as
necessary), after which the image section and bin factors are
applied. In both cases, the data is automatically converted from FITS
to native format, if necessary.
<P>
The first argument is the Funtools handle returned by 
<A HREF="./library.html#funopen">FunOpen()</A>.  The second <B>buf</B>
argument is a pointer to a data buffer to fill. If NULL is specified,
FunImageGet will allocate a buffer of the appropriate size. Generally
speaking, you always want Funtools to allocate the buffer because
the image dimensions will be determined by
<A HREF="./files.html#sections">Funtools image sectioning</A>
on the command line.
<P>
The third <B>plist</B> (i.e., parameter list) argument is a string
containing one or more comma-delimited <B>keyword=value</B>
parameters.  It can be used to specify the return data type using the
<B>bitpix=</B> keyword.  If no such keyword is specified in the plist
string, the data type of the returned image is the same as the data type
of the original input file, or is of type int for FITS binary tables.

<P>
If the <B>bitpix=</B> keyword is supplied in the plist string, the data
type of the returned image will be one of the supported FITS image
data types:
<UL>
<LI> 8 unsigned char
<LI> 16 short
<LI> 32 int
<LI> -32 float
<LI> -64 double
</UL>
For example:
<PRE>
  void *buf;
  /* extract data section into an image buffer */
  if( !(buf = FunImageGet(fun, NULL, NULL)) )
    gerror(stderr, "could not FunImageGet: %s\n", iname);
</PRE>
will allocate buf and retrieve the image in the file data format. In
this case, you will have to determine the data type (using the
FUN_SECT_BITPIX value in the 
<A HREF="./library.html#funinfoget">FunInfoGet()</A>
routine)
and then use a switch statement to process each data type:
<PRE>
  int bitpix;
  void *buf;
  unsigned char *cbuf;
  short *sbuf;
  int *ibuf;
  ...
  buf = FunImageGet(fun, NULL, NULL);
  FunInfoGet(fun, FUN_SECT_BITPIX,  &bitpix, 0);
  /* set appropriate data type buffer to point to image buffer */
  switch(bitpix){
  case 8:
    cbuf = (unsigned char *)buf; break;
  case 16:
    sbuf = (short *)buf; break;
  case 32:
    ibuf = (int *)buf; break;
 ...
</PRE>
See the 
<A HREF="./imblank.c">imblank example code</A>
for more details on how to process an image when the data type is not
specified beforehand.

<P>
It often is easier to specify the data type directly:
<PRE>
  double *buf;
  /* extract data section into a double image buffer */
  if( !(buf = FunImageGet(fun, NULL, "bitpix=-64")) )
    gerror(stderr, "could not FunImageGet: %s\n", iname);
</PRE>
will extract the image while converting to type double.

<P>
On success, a pointer to the image buffer is returned. (This will be
the same as the second argument, if NULL is not passed to the latter.)
On error, NULL is returned.

<P>
In summary, to retrieve image or row data into a binned image, you simply
call FunOpen() followed by 
<A HREF="./library.html#funimageget">FunImageGet()</A>.  Generally, you
then will want to call
<A HREF="./library.html#funinfoget">FunInfoGet()</A>
to retrieve the
axis dimensions (and data type) of the section you are processing
(so as to take account of sectioning and blocking of the original data):
<PRE>
  double *buf;
  int i, j;
  int dim1, dim2;
  ... other declarations, etc.

  /* open the input FITS file */
  if( !(fun = FunOpen(argv[1], "rc", NULL)) )
    gerror(stderr, "could not FunOpen input file: %s\n", argv[1]);

  /* extract and bin the data section into a double float image buffer */
  if( !(buf = FunImageGet(fun, NULL, "bitpix=-64")) )
    gerror(stderr, "could not FunImageGet: %s\n", argv[1]);

  /* get dimension information from funtools structure */
  FunInfoGet(fun, FUN_SECT_DIM1, &dim1, FUN_SECT_DIM2, &dim2, 0);

  /* loop through pixels and reset values below limit to value */
  for(i=0; i&lt;dim1*dim2; i++){
    if( buf[i] <= blimit ) buf[i] = bvalue;
  }
</PRE>

<P>
Another useful plist string value is "mask=all", which returns an
image populated with regions id values. Image pixels within a region
will contain the associated region id (region values start at 1), and
otherwise will contain a 0 value. Thus, the returned image is a
region mask which can be used to process the image data (which
presumably is retrieved by a separate call to FunImageGet) pixel by
pixel.

<P>
If a FITS binary table or a non-FITS raw event file is being binned
into an image, it is necessary to specify the two columns that will be
used in the 2D binning.  This usually is done on the command line
using the <B>bincols=(x,y)</B> keyword:
<PRE>
  funcnts "foo.ev[EVENTS,bincols=(detx,dety)]"
</PRE>

<P>
The full form of the <B>bincols=</B> specifier is:
<PRE>
  bincols=([xname[:tlmin[:tlmax:[binsiz]]]],[yname[:tlmin[:tlmax[:binsiz]]]])
</PRE>
where the tlmin, tlmax, and binsiz specifiers determine the image binning
dimensions:
<PRE>
  dim = (tlmax - tlmin)/binsiz     (floating point data)
  dim = (tlmax - tlmin)/binsiz + 1 (integer data)
</PRE>
These tlmin, tlmax, and binsiz specifiers can be omitted if TLMIN,
TLMAX, and TDBIN header parameters (respectively) are present in the
FITS binary table header for the column in question.  Note that if
only one parameter is specified, it is assumed to be tlmax, and tlmin
defaults to 1. If two parameters are specified, they are assumed to be
tlmin and tlmax.

<P>
If <B>bincols</B> is not specified on the command line, Funtools tries
to use appropriate defaults: it looks for the environment variable
FITS_BINCOLS (or FITS_BINKEY). Then it looks for the Chandra
parameters CPREF (or PREFX) in the FITS binary table header. Failing
this, it looks for columns named "X" and "Y" and if these are not
found, it looks for columns containing the characters "X" and "Y".
<P>
See <A HREF="./files.html#binning">Binning FITS Binary Tables and
Non-FITS Event Files</A> for more information.

<!-- =defdoc funimageput funimageput 3 -->

<!-- =section funimageput NAME -->
<H2><A NAME="funimageput">FunImagePut - put an image to a Funtools file</A></H2>
<!-- =section funimageput SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  int FunImagePut(Fun fun, void *buf, int dim1, int dim2, int bitpix,
                  char *plist)
</PRE>
</B>

<!-- =section funimageput DESCRIPTION -->
The <B>FunImagePut()</B> routine outputs an image array to a FITS
file. The image is written either as a primary header/data unit or as
an image extension, depending on whether other data have already been
written to the file.  That is, if the current file position is at the
beginning of the file, a primary HDU is written. Otherwise, an
image extension is written.

<P>
The first argument is the Funtools handle returned by 
<A HREF="./library.html#funopen">FunOpen()</A>.  The second <B>buf</B>
argument is a pointer to a data buffer to write.  The <B>dim1</B>and
<B>dim2</B> arguments that follow specify the dimensions of the image,
where dim1 corresponds to naxis1 and dim2 corresponds to naxis2.  The
<B>bitpix</B> argument specifies the data type of the image and can
have the following FITS-standard values:
<UL>
<LI> 8 unsigned char
<LI> 16 short
<LI> 32 int
<LI> -32 float
<LI> -64 double
</UL>

<P>
When <A HREF="./library.html#funtablerowput">FunTableRowPut()</A> is first
called for a given image, Funtools checks to see if the primary header
has already been written (by having previously written an image or a
binary table.) If not, this image is written to the primary HDU.
Otherwise, it is written to an image extension.
<P>
Thus, a simple program to generate a FITS image might look like this:
<PRE>
  int i;
  int dim1=512, dim2=512;
  double *dbuf;
  Fun fun;
  dbuf = malloc(dim1*dim2*sizeof(double));
  /* open the output FITS image, preparing to copy input params */
  if( !(fun = FunOpen(argv[1], "w", NULL)) )
    gerror(stderr, "could not FunOpen output file: %s\n", argv[1]);
  for(i=0; i&lt;(dim1*dim2); i++){
    ... fill dbuf ...
  }
  /* put the image (header will be generated automatically */
  if( !FunImagePut(fun, buf, dim1, dim2, -64, NULL) )
    gerror(stderr, "could not FunImagePut: %s\n", argv[1]);
  FunClose(fun);
  free(dbuf);
</PRE>

<P>
In addition, if a
<A HREF="./library.html#refhandle">Funtools reference handle</A>
was specified when this table was opened, the
parameters from this
<A HREF="./library.html#refhandle">Funtools reference handle</A>
are merged into the new image
header.  Furthermore, if a reference image was specified during 
<A HREF="./library.html#funopen">FunOpen()</A>, the values of
<B>dim1</B>, <B>dim2</B>, and <B>bitpix</B> in the calling sequence
can all be set to 0.  In this case, default values are taken from the
reference image section.  This is useful if you are reading an image
section in its native data format, processing it, and then writing
that section to a new FITS file.  See the 
<A HREF="./imblank.c">imblank example code</A>.

<P>
The data are assumed to be in the native machine format and will
automatically be swapped to FITS big-endian format if necessary.  This
behavior can be over-ridden with the <B>convert=[true|false]</B>
keyword in the <B>plist</B> param list string.

<p>
When you are finished writing the image, you should call 
<A HREF="./library.html#funflush">FunFlush()</A> to write out the FITS
image padding. However, this is not necessary if you subsequently call
FunClose() without doing any other I/O to the FITS file.

<!-- =defdoc funimagerowget funimagerowget 3 -->

<!-- =section funimagerowget NAME -->
<H2><A NAME="funimagerowget">FunImageRowGet - get row(s) of an image</A></H2>

<!-- =section funimagerowget SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  void *FunImageRowGet(Fun fun, void *buf, int rstart, int rstop,
                       char *plist)
</PRE>
</B>

<!-- =section funimagerowget DESCRIPTION -->
<P>
The <B>FunImageRowGet()</B> routine returns one or more image rows
from the specified section of a Funtools data file.  If the input data
are of type image, the array is generated by extracting the specified
image rows and then binning them according to the specified bin
factor.  If the input data are contained in a binary table or raw
event file, the rows are binned on the columns specified by the
<B>bincols=</B> keyword (using appropriate default columns as needed),
after which the image section and bin factors are applied.

<P>
The first argument is the Funtools handle returned by 
<A HREF="./library.html#funopen">FunOpen()</A>.  The second <B>buf</B>
argument is a pointer to a data buffer to fill. If NULL is specified,
FunImageGet() will allocate a buffer of the appropriate size.

<P>
The third and fourth arguments specify the first and last row to
retrieve.  Rows are counted starting from 1, up to the value of
FUN_YMAX(fun).  The final <B>plist</B> (i.e., parameter list) argument
is a string containing one or more comma-delimited
<B>keyword=value</B> parameters.  It can be used to specify the return
data type using the <B>bitpix=</B> keyword.  If no such keyword is
specified in the plist string, the data type of the image is the same
as the data type of the original input file, or is of type int for
FITS binary tables.

<P>
If the <B>bitpix=</B>value is supplied in the plist string, the data
type of the returned image will be one of the supported FITS image
data types:
<UL>
<LI> 8 unsigned char
<LI> 16 short
<LI> 32 int
<LI> -32 float
<LI> -64 double
</UL>

<P>
For example:
<PRE>
  double *drow;
  Fun fun;
  ... open files ...
  /* get section dimensions */
  FunInfoGet(fun, FUN_SECT_DIM1, &dim1, FUN_SECT_DIM2, &dim2, 0);
  /* allocate one line's worth */
  drow = malloc(dim1*sizeof(double));
  /* retrieve and process each input row (starting at 1) */
  for(i=1; i <= dim2; i++){
    if( !FunImageRowGet(fun, drow, i, i, "bitpix=-64") )
      gerror(stderr, "can't FunImageRowGet: %d %s\n", i, iname);
      /* reverse the line */
      for(j=1; j<=dim1; j++){
        ... process drow[j-1] ...
      }
  }
  ...
</PRE>

<P>
On success, a pointer to the image buffer is returned. (This will be
the same as the second argument, if NULL is not passed to the latter.)
On error, NULL is returned.  Note that the considerations described
above for specifying binning columns in 
<A HREF="./library.html#funimageget">FunImageGet()</A> also apply to
<B>FunImageRowGet()</B>.

<!-- =defdoc funimagerowput funimagerowput 3 -->

<!-- =section funimagerowput NAME -->
<H2><A NAME="funimagerowput">FunImageRowPut - put row(s) of an image</A></H2>

<!-- =section funimagerowput SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  void *FunImageRowPut(Fun fun, void *buf, int rstart, int rstop,
                       int dim1, int dim2, int bitpix, char *plist)
</PRE>
</B>

<!-- =section funimagerowput DESCRIPTION -->
<P>
The <B>FunImageRowPut()</B> routine writes one or more image rows to
the specified FITS image file.  The first argument is the Funtools
handle returned by <A HREF="./library.html#funopen">FunOpen()</A>.
The second <B>buf</B> argument is a pointer to the row data buffer,
while the third and fourth arguments specify the starting and ending
rows to write.  Valid rows values range from 1 to dim2, i.e., row is
one-valued.

<P>
The <B>dim1</B>and <B>dim2</B> arguments that follow specify the
dimensions, where dim1 corresponds to naxis1 and dim2 corresponds to
naxis2.  The <B>bitpix</B> argument data type of the image and can
have the following FITS-standard values:
<UL>
<LI> 8 unsigned char
<LI> 16 short
<LI> 32 int
<LI> -32 float
<LI> -64 double
</UL>

For example:
<PRE>
  double *drow;
  Fun fun, fun2;
  ... open files ...
  /* get section dimensions */
  FunInfoGet(fun, FUN_SECT_DIM1, &dim1, FUN_SECT_DIM2, &dim2, 0);
  /* allocate one line's worth */
  drow = malloc(dim1*sizeof(double));
  /* retrieve and process each input row (starting at 1) */
  for(i=1; i <= dim2; i++){
    if( !FunImageRowGet(fun, drow, i, i, "bitpix=-64") )
      gerror(stderr, "can't FunImageRowGet: %d %s\n", i, iname);
    ... process drow ...
    if( !FunImageRowPut(fun2, drow, i, i, 64, NULL) )
      gerror(stderr, "can't FunImageRowPut: %d %s\n", i, oname);
  }
  ...
</PRE>

<P>
The data are assumed to be in the native machine format and will
automatically be swapped to big-endian FITS format if necessary.  This
behavior can be over-ridden with the <B>convert=[true|false]</B>
keyword in the <B>plist</B> param list string.

<p>
When you are finished writing the image, you should call 
<A HREF="./library.html#funflush">FunFlush()</A> to write out the FITS
image padding. However, this is not necessary if you subsequently call
FunClose() without doing any other I/O to the FITS file.

<!-- =defdoc funcolumnselect funcolumnselect 3 -->

<!-- =section funcolumnselect NAME -->
<H2><A NAME="funcolumnselect">FunColumnSelect - select Funtools columns</A></H2>
<!-- =section funcolumnselect SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  int FunColumnSelect(Fun fun, int size, char *plist, 
                      char *name1, char *type1, char *mode1, int offset1,
                      char *name2, char *type2, char *mode2, int offset2,
                      ...,
                      NULL)

  int FunColumnSelectArr(Fun fun, int size, char *plist, 
                         char **names, char **types, char **modes,
                         int *offsets, int nargs);
</PRE>
</B>

<!-- =section funcolumnselect DESCRIPTION -->
The <B>FunColumnSelect()</B> routine is used to select the columns
from a Funtools binary table extension or raw event file for
processing. This routine allows you to specify how columns in a file
are to be read into a user record structure or written from a user
record structure to an output FITS file.

<P>
The first argument is the Fun handle associated with this set of
columns. The second argument specifies the size of the user record
structure into which columns will be read.  Typically, the sizeof()
macro is used to specify the size of a record structure.  The third
argument allows you to specify keyword directives for the selection
and is described in more detail below.

<P>
Following the first three required arguments is a variable length list of
column specifications.  Each column specification will consist of four
arguments:
<UL>
<LI> <B>name</B>: the name of the column

<LI> <B>type</B>: the data type of the column as it will be stored in
the user record struct (not the data type of the input file). The
following basic data types are recognized:
<UL>
<LI>A: ASCII characters
<LI>B: unsigned 8-bit char
<LI>I: signed 16-bit int
<LI>U: unsigned 16-bit int (not standard FITS)
<LI>J: signed 32-bit int
<LI>V: unsigned 32-bit int (not standard FITS)
<LI>E: 32-bit float
<LI>D: 64-bit float
</UL>
The syntax used is similar to that which defines the TFORM parameter
in FITS binary tables. That is, a numeric repeat value can precede
the type character, so that "10I" means a vector of 10 short ints, "E"
means a single precision float, etc.  Note that the column value from
the input file will be converted to the specified data type as the
data is read by
<A HREF="./library.html#funtablerowget">FunTableRowGet()</A>.

<P>
[ A short digression regarding bit-fields: Special attention is
required when reading or writing the FITS bit-field type
("X"). Bit-fields almost always have a numeric repeat character
preceding the 'X' specification. Usually this value is a multiple of 8
so that bit-fields fit into an integral number of bytes. For all
cases, the byte size of the bit-field B is (N+7)/8, where N is the
numeric repeat character.

<p>
A bit-field is most easily declared in the user struct as an array of
type char of size B as defined above. In this case, bytes are simply
moved from the file to the user space.  If, instead, a short or int
scalar or array is used, then the algorithm for reading the bit-field
into the user space depends on the size of the data type used along
with the value of the repeat character.  That is, if the user data
size is equal to the byte size of the bit-field, then the data is
simply moved (possibly with endian-based byte-swapping) from one to
the other. If, on the other hand, the data storage is larger than the
bit-field size, then a data type cast conversion is performed to move
parts of the bit-field into elements of the array.  Examples will help
make this clear:

<UL>
<LI> If the file contains a 16X bit-field and user space specifies a 2B
char array[2], then the bit-field is moved directly into the char array.

<LI> If the file contains a 16X bit-field and user space specifies a 1I
scalar short int, then the bit-field is moved directly into the short int.

<LI> If the file contains a 16X bit-field and user space specifies a 1J
scalar int, then the bit-field is type-cast to unsigned int before
being moved (use of unsigned avoids possible sign extension).

<LI> If the file contains a 16X bit-field and user space specifies a 2J
int array[2], then the bit-field is handled as 2 chars, each of which
are type-cast to unsigned int before being moved (use of unsigned
avoids possible sign extension).

<LI> If the file contains a 16X bit-field and user space specifies a 1B
char, then the bit-field is treated as a char, i.e., truncation will
occur.

<LI> If the file contains a 16X bit-field and user space specifies a 4J
int array[4], then the results are undetermined.

</UL>
For all user data types larger than char, the bit-field is byte-swapped
as necessary to convert to native format, so that bits in the
resulting data in user space can be tested, masked, etc. in the same
way regardless of platform.]

<P>
In addition to setting data type and size, the <B>type</B>
specification allows a few ancillary parameters to be set, using the
full syntax for <B>type</B>:
<PRE>
 [@][n]&lt;type&gt;[[['B']poff]][:[tlmin[:tlmax[:binsiz]]]]
</PRE>

<P>
The special character "@" can be prepended to this specification to
indicated that the data element is a pointer in the user record,
rather than an array stored within the record.

<P>
The [n] value is an integer that specifies the
number of elements that are in this column (default is 1). TLMIN,
TLMAX, and BINSIZ values also can be specified for this column after
the type, separated by colons. If only one such number is specified,
it is assumed to be TLMAX, and TLMIN  and BINSIZ are set to 1.

<P>
The [poff] value can be used to specify the offset into an
array. By default, this offset value is set to zero and the data
specified starts at the beginning of the array. The offset usually
is specified in terms of the data type of the column. Thus an offset
specification of [5] means a 20-byte offset if the data type is a
32-bit integer, and a 40-byte offset for a double. If you want to
specify a byte offset instead of an offset tied to the column data type,
precede the offset value with 'B', e.g. [B6] means a 6-bye offset,
regardless of the column data type.

The [poff] is especially useful in conjunction with the pointer @
specification, since it allows the data element to anywhere stored
anywhere in the allocated array.  For example, a specification such as
"@I[2]" specifies the third (i.e., starting from 0) element in the
array pointed to by the pointer value. A value of "@2I[4]" specifies
the fifth and sixth values in the array. For example, consider the
following specification: <PRE>

  typedef struct EvStruct{
    short x[4], *atp;
  } *Event, EventRec;
  /* set up the (hardwired) columns */
  FunColumnSelect( fun, sizeof(EventRec), NULL,
                   "2i",    "2I  ",    "w", FUN_OFFSET(Event, x),
                   "2i2",   "2I[2]",   "w", FUN_OFFSET(Event, x),
                   "at2p",  "@2I",     "w", FUN_OFFSET(Event, atp),
                   "at2p4", "@2I[4]",  "w", FUN_OFFSET(Event, atp),
                   "atp9",  "@I[9]",   "w", FUN_OFFSET(Event, atp),
                   "atb20", "@I[B20]", "w", FUN_OFFSET(Event, atb),
                   NULL);
</PRE>
Here we have specified the following columns:
<UL>
<LI> 2i: two short ints in an array which is stored as part the
record
<LI> 2i2: the 3rd and 4th elements of an array which is stored
as part of the record
<LI> an array of at least 10 elements, not stored in the record but
allocated elsewhere, and used by three different columns:
<UL>
<LI> at2p: 2 short ints which are the first 2 elements of the allocated array
<LI> at2p4: 2 short ints which are the 5th and 6th elements of 
the allocated array
<LI> atp9: a short int which is the 10th element of the allocated array
</UL>
<LI> atb20: a short int which is at byte offset 20 of another allocated array
</UL>
In this way, several columns can be specified, all of which are in a
single array. <B>NB</B>: it is the programmer's responsibility to
ensure that specification of a positive value for poff does not point
past the end of valid data.

<LI> <B>read/write mode</B>: "r" means that the column is read from an
input file into user space by 
<A HREF="./library.html#funtablerowget">FunTableRowGet()</A>, "w" means that
the column is written to an output file. Both can specified  at the same
time.

<LI> <B>offset</B>: the offset into the user data to store
this column. Typically, the macro FUN_OFFSET(recname, colname) is used
to define the offset into a record structure.
</UL>

<P>
When all column arguments have been specified, a final NULL argument
must added to signal the column selection list.

<P>
As an alternative to the varargs
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>
routine, a non-varargs routine called
<A HREF="./library.html#funcolumnselect">FunColumnSelectArr()</A>
also is available. The first three arguments (fun, size, plist) of this
routine are the same as in
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>.
Instead of a variable
argument list, however,
<A HREF="./library.html#funcolumnselect">FunColumnSelectArr()</A>
takes 5 additional arguments. The first 4 arrays arguments contain the
names, types, modes, and offsets, respectively, of the columns being
selected. The final argument is the number of columns that are
contained in these arrays. It is the user's responsibility to free
string space allocated in these arrays.

<P>
Consider the following example:
<PRE>
  typedef struct evstruct{
    int status;
    float pi, pha, *phas;
    double energy;
  } *Ev, EvRec;

  FunColumnSelect(fun, sizeof(EvRec), NULL,
    "status",  "J",     "r",   FUN_OFFSET(Ev, status),
    "pi",      "E",     "r",  FUN_OFFSET(Ev, pi),
    "pha",     "E",     "r",  FUN_OFFSET(Ev, pha),
    "phas",    "@9E",   "r",  FUN_OFFSET(Ev, phas),
    NULL);
</PRE>
<P>
Each time a row is read into the Ev struct, the "status" column is
converted to an int data type (regardless of its data type in the
file) and stored in the status value of the struct.  Similarly, "pi"
and "pha", and the phas vector are all stored as floats. Note that the
"@" sign indicates that the "phas" vector is a pointer to a 9 element
array, rather than an array allocated in the struct itself. The row
record can then be processed as required:
<PRE>
  /* get rows -- let routine allocate the row array */
  while( (ebuf = (Ev)FunTableRowGet(fun, NULL, MAXROW, NULL, &got)) ){
    /* process all rows */
    for(i=0; i&lt;got; i++){
      /* point to the i'th row */
      ev = ebuf+i;
      ev->pi = (ev->pi+.5);
      ev->pha = (ev->pi-.5);
    }
</PRE>

<P>
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>
can also be called to define "writable" columns in order to generate a FITS
Binary Table, without reference to any input columns.  For
example, the following will generate a 4-column FITS binary table when
<A HREF="./library.html#funtablerowput">FunTableRowPut()</A> is used to
write Ev records:

<PRE>
  typedef struct evstruct{
    int status;
    float pi, pha
    double energy;
  } *Ev, EvRec;

  FunColumnSelect(fun, sizeof(EvRec), NULL,
    "status",  "J",     "w",   FUN_OFFSET(Ev, status),
    "pi",      "E",     "w",   FUN_OFFSET(Ev, pi),
    "pha",     "E",     "w",   FUN_OFFSET(Ev, pha),
    "energy",  "D",       "w",   FUN_OFFSET(Ev, energy),
    NULL);
</PRE>
All columns are declared to be write-only, so presumably the column
data is being generated or read from some other source.

<P>
In addition, 
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>
can be called to define <B>both</B> "readable" and "writable" columns.
In this case, the "read" columns
are associated with an input file, while the "write" columns are
associated with the output file. Of course, columns can be specified as both
"readable" and "writable", in which case they are read from input
and (possibly modified data values are) written to the output.
The 
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>
call itself is made by passing the input Funtools handle, and it is
assumed that the output file has been opened using this input handle
as its
<A HREF="./library.html#refhandle">Funtools reference handle</A>.

<P>
Consider the following example:
<PRE>
  typedef struct evstruct{
    int status;
    float pi, pha, *phas;
    double energy;
  } *Ev, EvRec;

  FunColumnSelect(fun, sizeof(EvRec), NULL,
    "status",  "J",     "r",   FUN_OFFSET(Ev, status),
    "pi",      "E",     "rw",  FUN_OFFSET(Ev, pi),
    "pha",     "E",     "rw",  FUN_OFFSET(Ev, pha),
    "phas",    "@9E",   "rw",  FUN_OFFSET(Ev, phas),
    "energy",  "D",     "w",   FUN_OFFSET(Ev, energy),
    NULL);
</PRE>
As in the "read" example above, each time an row is read into the Ev
struct, the "status" column is converted to an int data type
(regardless of its data type in the file) and stored in the status
value of the struct.  Similarly, "pi" and "pha", and the phas vector
are all stored as floats.  Since the "pi", "pha", and "phas" variables
are declared as "writable" as well as "readable", they also will be
written to the output file.  Note, however, that the "status" variable
is declared as "readable" only, and hence it will not be written to
an output file.  Finally, the "energy" column is declared as
"writable" only, meaning it will not be read from the input file. In
this case, it can be assumed that "energy" will be calculated in the
program before being output along with the other values.

<P>
In these simple cases, only the columns specified as "writable" will
be output using 
<A HREF="./library.html#funtablerowput">FunTableRowPut()</A>.  However,
it often is the case that you want to merge the user columns back in
with the input columns, even in cases where not all of the input
column names are explicitly read or even known. For this important
case, the <B>merge=[type]</B> keyword is provided in the plist string.

<P>
The <B>merge=[type]</B> keyword tells Funtools to merge the columns from
the input file with user columns on output.  It is normally used when
an input and output file are opened and the input file provides the
<A HREF="./library.html#refhandle">Funtools reference handle</A>
for the output file. In this case, each time 
<A HREF="./library.html#funtablerowget">FunTableRowGet()</A> is called, the
raw input rows are saved in a special buffer. If 
<A HREF="./library.html#funtablerowput">FunTableRowPut()</A> then is called
(before another call to 
<A HREF="./library.html#funtablerowget">FunTableRowGet()</A>), the contents
of the raw input rows are merged with the user rows according to the
value of <B>type</B> as follows:

<UL>
<LI> <B>update</B>: add new user columns, and update value of existing ones (maintaining the input data type)

<LI> <B>replace</B>: add new user columns, and replace the data type
and value of existing ones.  (Note that if tlmin/tlmax values are not
specified in the replacing column, but are specified in the original
column being replaced, then the original tlmin/tlmax values are used
in the replacing column.)

<LI> <B>append</B>: only add new columns, do not "replace" or "update" existing ones
</UL>

<P>
Consider the example above. If <B>merge=update</B> is specified in the
plist string, then "energy" will be added to the input columns, and
the values of "pi", "pha", and "phas" will be taken from the user
space (i.e., the values will be updated from the original values, if
they were changed by the program).  The data type for "pi", "pha", and
"phas" will be the same as in the original file.  If
<B>merge=replace</B> is specified, both the data type and value of
these three input columns will be changed to the data type and value
in the user structure.  If <B>merge=append</B> is specified, none of
these three columns will be updated, and only the "energy" column will
be added. Note that in all cases, "status" will be written from the
input data, not from the user record, since it was specified as read-only.

<P>
Standard applications will call 
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>
to define user columns. However, if this routine is not called, the
default behavior is to transfer all input columns into user space. For
this purpose a default record structure is defined such that each data
element is properly aligned on a valid data type boundary.  This
mechanism is used by programs such as fundisp and funtable to process
columns without needing to know the specific names of those columns.
It is not anticipated that users will need such capabilities (contact
us if you do!)

<p>
By default, <A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>
reads/writes rows to/from an "array of structs", where each struct contains
the column values for a single row of the table. This means that the
returned values for a given column are not contiguous. You can
set up the IO to return a "struct of arrays" so that each of the
returned columns are contiguous by specifying <B>org=structofarrays</B>
(abbreviation: <B>org=soa</B>) in the plist. 
(The default case is <B>org=arrayofstructs</B> or <B>org=aos</B>.)

<P>
For example, the default setup to retrieve rows from a table would be
to define a record structure for a single event and then call
 <A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>
as follows:
<PRE>
  typedef struct evstruct{
    short region;
    double x, y;
    int pi, pha;
    double time;
  } *Ev, EvRec;

  got = FunColumnSelect(fun, sizeof(EvRec), NULL,
                        "x",       "D:10:10", mode, FUN_OFFSET(Ev, x),
                        "y",       "D:10:10", mode, FUN_OFFSET(Ev, y),
                        "pi",      "J",       mode, FUN_OFFSET(Ev, pi),
                        "pha",     "J",       mode, FUN_OFFSET(Ev, pha),
                        "time",    "1D",      mode, FUN_OFFSET(Ev, time),
                        NULL);
</PRE>
Subsequently, each call to
<HREF="./library.html#funtablerowget">FunTableRowGet()</A>
will return an array of structs, one for each returned row. If instead you
wanted to read columns into contiguous arrays, you specify <B>org=soa</B>:
<PRE>
  typedef struct aevstruct{
    short region[MAXROW];
    double x[MAXROW], y[MAXROW];
    int pi[MAXROW], pha[MAXROW];
    double time[MAXROW];
  } *AEv, AEvRec;

  got = FunColumnSelect(fun, sizeof(AEvRec), "org=soa",
                      "x",       "D:10:10", mode, FUN_OFFSET(AEv, x),
                      "y",       "D:10:10", mode, FUN_OFFSET(AEv, y),
                      "pi",      "J",       mode, FUN_OFFSET(AEv, pi),
                      "pha",     "J",       mode, FUN_OFFSET(AEv, pha),
                      "time",    "1D",      mode, FUN_OFFSET(AEv, time),
                      NULL);
</PRE>
Note that the only modification to the call is in the plist string.

<P>
Of course, instead of using staticly allocated arrays, you also can specify
dynamically allocated pointers:
<PRE>
  /* pointers to arrays of columns (used in struct of arrays) */
  typedef struct pevstruct{
    short *region;
    double *x, *y;
    int *pi, *pha;
    double *time;
  } *PEv, PEvRec;

  got = FunColumnSelect(fun, sizeof(PEvRec), "org=structofarrays",
                      "$region", "@I",       mode, FUN_OFFSET(PEv, region),
                      "x",       "@D:10:10", mode, FUN_OFFSET(PEv, x),
                      "y",       "@D:10:10", mode, FUN_OFFSET(PEv, y),
                      "pi",      "@J",       mode, FUN_OFFSET(PEv, pi),
                      "pha",     "@J",       mode, FUN_OFFSET(PEv, pha),
                      "time",    "@1D",      mode, FUN_OFFSET(PEv, time),
                      NULL);
</PRE>
Here, the actual storage space is either allocated by the user or by the 
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A> call).

<P>
In all of the above cases, the same call is made to retrieve rows, e.g.:
<PRE>
    buf = (void *)FunTableRowGet(fun, NULL, MAXROW, NULL, &got);
</PRE>
However, the individual data elements are accessed differently.
For the default case of an "array of structs", the
individual row records are accessed using:
<PRE>
  for(i=0; i&lt;got; i++){
    ev = (Ev)buf+i;
    fprintf(stdout, "%.2f\t%.2f\t%d\t%d\t%.4f\t%.4f\t%21.8f\n",
            ev->x, ev->y, ev->pi, ev->pha, ev->dx, ev->dy, ev->time);
  }
</PRE>
For a struct of arrays or a struct of array pointers, we have a single struct
through which we access individual columns and rows using:
<PRE>
  aev = (AEv)buf;
  for(i=0; i&lt;got; i++){
    fprintf(stdout, "%.2f\t%.2f\t%d\t%d\t%.4f\t%.4f\t%21.8f\n",
            aev->x[i], aev->y[i], aev->pi[i], aev->pha[i], 
            aev->dx[i], aev->dy[i], aev->time[i]);
  }
</PRE>
Support for struct of arrays in the 
<A HREF="./library.html#funtablerowput">FunTableRowPut()</A>
call is handled analogously.

<P>
See the <A HREF="./evread.c">evread example code</A>
and
<A HREF="./evmerge.c">evmerge example code</A>
for working examples of how 
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A> is used.

<!-- =defdoc funcolumnactivate funcolumnactivate 3 -->

<!-- =section funcolumnactivate NAME -->
<H2><A NAME="funcolumnactivate">FunColumnActivate - activate Funtools columns</A></H2>

<!-- =section funcolumnactivate SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  void FunColumnActivate(Fun fun, char *s, char *plist)
</PRE>
</B>

<!-- =section funcolumnactivate DESCRIPTION -->
<P>
The <B>FunColumnActivate()</B> routine determines which columns (set up
by <A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>)
ultimately will be read and/or written.  By default, all columns that
are selected using 
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>
are activated.  The 
<A HREF="./library.html#funcolumnactivate">FunColumnActivate()</A>
routine can be used to turn off/off activation of specific columns.

<P>
The first argument is the Fun handle associated with this set of
columns.  The second argument is a space-delimited list of columns to
activate or de-activate. Columns preceded by "+" are activated and
columns preceded by a "-" are de-activated. If a column is named
without "+" or "-", it is activated. The reserved strings "$region"
and '$n' are used to activate a special columns containing the filter
region value and row value, respectively, associated with
this row. For example, if a filter containing two circular regions is
specified as part of the Funtools file name, this column will contain
a value of 1 or 2, depending on which region that row was in. The
reserved strings "$x" and "$y" are used to activate the current
binning columns. Thus, if the columns DX and DY are specified as
binning columns:
<PRE>
  [sh $] fundisp foo.fits[bincols=(DX,DY)]
</PRE>
then "$x" and "$y" will refer to these columns in a call to
<A HREF="./library.html#funcolumnactivate">FunColumnActivate()</A>.

<P>
In addition, if the activation string contains only columns to be
activated, then the routine will de-activate all other columns.
Similarly, if the activation string contains only
columns to de-activate, then the routine will activate all other columns
before activating the list.  This makes it simple to change the
activation state of all columns without having to know all of the
column names. For example:
<UL>
<LI> <B>"pi pha time"</B>     # only these three columns will be active
<LI> <B>"-pi -pha -time"</B>  # all but these columns will be active
<LI> <B>"pi -pha"</B>         # only pi is active, pha is not, others are not
<LI> <B>"+pi -pha"</B>        # same as above
<LI> <B>"pi -pha -time"</B>   # only pi is active, all others are not
<LI> <B>"pi pha"</B>          # pha and pi are active, all others are not
<LI> <B>"pi pha -x -y"</B>    # pha and pi are active, all others are not
</UL>

<p>
You can use the column activation list to reorder columns, since
columns are output in the order specified. For example:
<PRE>
  # default output order
  fundisp snr.ev'[cir 512 512 .1]' 
         X        Y      PHA       PI                  TIME       DX       DY
  -------- -------- -------- -------- --------------------- -------- --------
       512      512        6        7     79493997.45854475      578      574
       512      512        8        9     79494575.58943175      579      573
       512      512        5        6     79493631.03866175      578      575
       512      512        5        5     79493290.86521725      578      575
       512      512        8        9     79493432.00990875      579      573

  # re-order the output by specifying explicit order
  fundisp snr.ev'[cir 512 512 .1]' "time x y dy dx pi pha"
                   TIME        X        Y       DY       DX       PI      PHA
  --------------------- -------- -------- -------- -------- -------- --------
      79493997.45854475      512      512      574      578        7        6
      79494575.58943175      512      512      573      579        9        8
      79493631.03866175      512      512      575      578        6        5
      79493290.86521725      512      512      575      578        5        5
      79493432.00990875      512      512      573      579        9        8
</PRE>

<P>
A "+" sign by itself means to activate all columns, so that you can reorder
just a few columns without specifying all of them:
<PRE>
  # reorder 3 columns and then output the rest
  fundisp snr.ev'[cir 512 512 .1]' "time pi pha +"
                   TIME       PI      PHA        Y        X       DX       DY
  --------------------- -------- -------- -------- -------- -------- --------
      79493997.45854475        7        6      512      512      578      574
      79494575.58943175        9        8      512      512      579      573
      79493631.03866175        6        5      512      512      578      575
      79493290.86521725        5        5      512      512      578      575
      79493432.00990875        9        8      512      512      579      573
</PRE>
The column activation/deactivation is performed in the order of the
specified column arguments. This means you can mix "+", "-" (which
de-activates all columns) and specific column names to reorder and
select columns in one command. For example, consider the following:
<PRE>
  # reorder and de-activate
  fundisp snr.ev'[cir 512 512 .1]' "time pi pha + -x -y"
                   TIME       PI      PHA       DX       DY
  --------------------- -------- -------- -------- --------
      79493997.45854475        7        6      578      574
      79494575.58943175        9        8      579      573
      79493631.03866175        6        5      578      575
      79493290.86521725        5        5      578      575
      79493432.00990875        9        8      579      573
</PRE>
We first activate "time", "pi", and "pha" so that they are output first.
We then activate all of the other columns, and then de-activate "x" and "y".
Note that this is different from:
<PRE>
  # probably not what you want ...
  fundisp snr.ev'[cir 512 512 .1]' "time pi pha -x -y +"
                   TIME       PI      PHA        Y        X       DX       DY
  --------------------- -------- -------- -------- -------- -------- --------
      79493997.45854475        7        6      512      512      578      574
      79494575.58943175        9        8      512      512      579      573
      79493631.03866175        6        5      512      512      578      575
      79493290.86521725        5        5      512      512      578      575
      79493432.00990875        9        8      512      512      579      573
</PRE>
Here, "x" and "y" are de-activated, but then all columns including "x" and
"y" are again re-activated.

<p>
Typically, 
<A HREF="./library.html#funcolumnactivate">FunColumnActivate()</A> uses a
list of columns that are passed into the program from the command line.  For
example, the code for funtable contains the following:
<PRE>
  char *cols=NULL;

  /* open the input FITS file */
  if( !(fun = FunOpen(argv[1], "rc", NULL)) )
    gerror(stderr, "could not FunOpen input file: %s\n", argv[1]);

  /* set active flag for specified columns */
  if( argc >= 4 ) cols = argv[3];
  FunColumnActivate(fun, cols, NULL);
</PRE>

The <A HREF="./library.html#funopen">FunOpen()</A> call sets the
default columns to be all columns in the input file. The 
<A HREF="./library.html#funcolumnactivate">FunColumnActivate()</A> call
then allows the user to control which columns ultimately will be
activated (i.e., in this case, written to the new file).  For example:
<PRE>
  funtable test.ev foo.ev "pi pha time"
</PRE>
will process only the three columns mentioned, while:
<PRE>
  funtable test.ev foo.ev "-time"
</PRE>
will process all columns except "time".

<P>
If <A HREF="./library.html#funcolumnactivate">FunColumnActivate()</A>
is called with a null string, then the environment variable
<B>FUN_COLUMNS</B> will be used to provide a global value, if present.
This is the reason why we call the routine even if no columns
are specified on the command line (see example above), instead
of calling it this way:
<PRE>
  /* set active flag for specified columns */
  if( argc >= 4 ){
    FunColumnActivate(fun, argv[3], NULL);
  }
</PRE>

<!-- =defdoc funcolumnlookup funcolumnlookup 3 -->

<!-- =section funcolumnlookup NAME -->
<H2><A NAME="funcolumnlookup">FunColumnLookup - lookup a Funtools column</A></H2>
<!-- =section funcolumnlookup SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  int FunColumnLookup(Fun fun, char *s, int which,
                      char **name, int *type, int *mode,
                      int *offset, int *n, int *width)
</PRE>
</B>

<!-- =section funcolumnlookup DESCRIPTION -->
<P>
The <B>FunColumnLookup()</B> routine returns information about a named
(or indexed) column.  The first argument is the Fun handle associated
with this set of columns. The second argument is the name of the
column to look up.  If the name argument is NULL, the argument that
follows is the zero-based index into the column array of the column
for which information should be returned.  The next argument is a
pointer to a char *, which will contain the name of the column. The
arguments that follow are the addresses of int values into which
the following information will be returned:
<UL>
<LI> <B>type</B>: data type of column:
<UL>
<LI>A: ASCII characters
<LI>B: unsigned 8-bit char
<LI>I: signed 16-bit int
<LI>U: unsigned 16-bit int (not standard FITS)
<LI>J: signed 32-bit int
<LI>V: unsigned 32-bit int (not standard FITS)
<LI>E: 32-bit float
<LI>D: 64-bit float
</UL>
<LI> <B>mode</B>: bit flag status of column, including:
<UL>
<LI> COL_ACTIVE      1 is column activated?
<LI> COL_IBUF        2 is column in the raw input data?
<LI> COL_PTR         4 is column a pointer to an array?
<LI> COL_READ      010 is read mode selected?
<LI> COL_WRITE     020 is write mode selected?
<LI> COL_REPLACEME 040 is this column being replaced by user data?
</UL>
<LI> <B>offset</B>: byte offset in struct
<LI> <B>n</B>: number of elements (i.e. size of vector) in this column
<LI> <B>width</B>: size in bytes of this column
</UL>
If the named column exists, the routine returns a positive integer,
otherwise zero is returned. (The positive integer is the index+1 into
the column array where this column was located.)

If NULL is passed as the return address of one (or more) of these
values, no data is passed back for that information.  For
example:
<PRE>
  if( !FunColumnLookup(fun, "phas", 0, NULL NULL, NULL, NULL, &npha, NULL) )
    gerror(stderr, "can't find phas column\n");
</PRE>
only returns information about the size of the phas vector.

<!-- =defdoc funtablerowget funtablerowget 3 -->

<!-- =section funtablerowget NAME -->
<H2><A NAME="funtablerowget">FunTableRowGet - get Funtools rows</A></H2>

<!-- =section funtablerowget SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  void *FunTableRowGet(Fun fun, void *rows, int maxrow, char *plist,
                       int *nrow)
</PRE>
</B>

<!-- =section funtablerowget DESCRIPTION -->
<P>
The <B>FunTableRowGet()</B> routine retrieves rows from a Funtools
binary table or raw event file, and places the values of columns
selected by <A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>
into an array of user structs.  Selected column values are
automatically converted to the specified user data type (and to native
data format) as necessary.

<P>
The first argument is the Fun handle associated with this row data.
The second <B>rows</B> argument is the array of user structs into
which the selected columns will be stored. If NULL is passed, the
routine will automatically allocate space for this array. (This
includes proper allocation of pointers within each struct, if the "@"
pointer type is used in the selection of columns.  Note that if you
pass NULL in the second argument, you should free this space using the
standard free() system call when you are finished with the array of
rows.)  The third <B>maxrow</B> argument specifies the maximum number
of rows to be returned. Thus, if <B>rows</B> is allocated by the
user, it should be at least of size maxrow*sizeof(evstruct).  

<P>
The fourth <B>plist</B> argument is a param list string.  Currently,
the keyword/value pair "mask=transparent" is supported in the plist
argument.  If this string is passed in the call's plist argument, then
all rows are passed back to the user (instead of just rows passing
the filter). This is only useful when 
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A> also is
used to specify "$region" as a column to return for each row.  In
such a case, rows found within a region have a returned region value
greater than 0 (corresponding to the region id of the region in which
they are located), rows passing the filter but not in a region have
region value of -1, and rows not passing any filter have region
value of 0. Thus, using "mask=transparent" and the returned region
value, a program can process all rows and decide on an action based
on whether a given row passed the filter or not.

<P>
The final argument is a pointer to an int variable that will return
the actual number of rows returned.  The routine returns a pointer to
the array of stored rows, or NULL if there was an error. (This pointer
will be the same as the second argument, if the latter is non-NULL).
<PRE>
  /* get rows -- let routine allocate the row array */
  while( (buf = (Ev)FunTableRowGet(fun, NULL, MAXROW, NULL, &got)) ){
    /* process all rows */
    for(i=0; i&lt;got; i++){
      /* point to the i'th row */
      ev = buf+i;
      /* rearrange some values. etc. */
      ev->energy = (ev->pi+ev->pha)/2.0;
      ev->pha = -ev->pha;
      ev->pi = -ev->pi;
    }
    /* write out this batch of rows */
    FunTableRowPut(fun2, buf, got, 0, NULL);
    /* free row data */
    if( buf ) free(buf);
  }
</PRE>
As shown above, successive calls to 
<A HREF="./library.html#funtablerowget">FunTableRowGet()</A> will return the
next set of rows from the input file until all rows have been read,
i.e., the routine behaves like sequential Unix I/O calls such as
fread(). See <A HREF="./evmerge.c">evmerge example code</A> for a
more complete example.

<P>
Note that FunTableRowGet() also can be called as FunEventsGet(), for
backward compatibility.

<!-- =defdoc funtablerowput funtablerowput 3 -->

<!-- =section funtablerowput NAME -->
<H2><A NAME="funtablerowput">FunTableRowPut - put Funtools rows</A></H2>

<!-- =section funtablerowput SYNOPSIS -->
<PRE>
<B>
int FunTableRowPut(Fun fun, void *rows, int nev, int idx, char *plist)
</B>
</PRE>

<!-- =section funtablerowput DESCRIPTION -->
The <B>FunTableRowPut()</B> routine writes rows to a FITS binary
table, taking its input from an array of user structs that contain
column values selected by a previous call to 
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>.  Selected
column values are automatically converted from native data format to
FITS data format as necessary.

<P>
The first argument is the Fun handle associated with this row data.
The second <B>rows</B> argument is the array of user structs to
output. The third <B>nrow</B> argument specifies the number number of
rows to write.  The routine will write <B>nrow</B> records, starting
from the location specified by <B>rows</B>.

<P>
The fourth <B>idx</B> argument is the index of the first raw input
row to write, in the case where rows from the user buffer are
being merged with their raw input row counterparts (see below). Note
that this <B>idx</B> value is has nothing to do with the
row buffer specified in argument 1.  It merely matches the row
being written with its corresponding (hidden) raw row.  Thus, if you
read a number of rows, process them, and then write them out all at
once starting from the first user row, the value of <B>idx</B>
should be 0:
<PRE>
  Ev ebuf, ev;
  /* get rows -- let routine allocate the row array */
  while( (ebuf = (Ev)FunTableRowGet(fun, NULL, MAXROW, NULL, &got)) ){
    /* process all rows */
    for(i=0; i&lt;got; i++){
      /* point to the i'th row */
      ev = ebuf+i;
      ...
    }
    /* write out this batch of rows, starting with the first */
    FunTableRowPut(fun2, (char *)ebuf, got, 0, NULL);
    /* free row data */
    if( ebuf ) free(ebuf);
  }
</PRE>

<P>
On the other hand, if you write out the rows one at a time (possibly
skipping rows), then, when writing the i'th row from the input
array of rows, set <B>idx</B> to the value of i:
<PRE>
  Ev ebuf, ev;
  /* get rows -- let routine allocate the row array */
  while( (ebuf = (Ev)FunTableRowGet(fun, NULL, MAXROW, NULL, &got)) ){
    /* process all rows */
    for(i=0; i&lt;got; i++){
      /* point to the i'th row */
      ev = ebuf+i;
      ...
      /* write out the current (i.e., i'th) row */
      FunTableRowPut(fun2, (char *)ev, 1, i, NULL);
    }
    /* free row data */
    if( ebuf ) free(ebuf);
  }
</PRE>

<P>
The final argument is a param list string that is not currently used.
The routine returns the number of rows output.  This should be equal
to the value passed in the third <B>nrow</B argument.

<P>
When <A HREF="./library.html#funtablerowput">FunTableRowPut()</A> is first
called for a given binary table, Funtools checks to see of the primary
header has already been written (either by writing a previous row
table or by writing an image.) If not, a dummy primary header is
written to the file specifying that an extension should be expected.
After this, a binary table header is automatically written containing
information about the columns that will populate this table.  In
addition, if a 
<A HREF="./library.html#refhandle">Funtools reference handle</A>
was specified when this table was opened, the parameters from this
<A HREF="./library.html#refhandle">Funtools reference handle</A>
are merged into the new binary table header.

<P>
In a typical Funtools row loop, you read rows using 
<A HREF="./library.html#funtablerowget">FunTableRowGet()</A>() and write
rows using FunTableRowPut(). The columns written by
FunTableRowPut()() are those defined as writable by a previous call to
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A>.  If
that call to FunColumnSelect also specified
<B>merge=[update|replace|append]</B>, then the entire corresponding
raw input row record will be merged with the output row according
to the <B>merge</B> specification (see 
<A HREF="./library.html#funcolumnselect">FunColumnSelect()</A> above).

<P>
A call to write rows can either be done once, after all rows in
the input batch have been processed, or it can be done (slightly less
efficiently) one row at a time (or anything in between). We do
recommend that you write all rows associated with a given batch of
input rows before reading new rows.  This is <B>required</B> if
you are merging the output rows with the raw input rows (since
the raw rows are destroyed with each successive call to get new rows).

For example:
<PRE>
  Ev buf, ev;
  ...
  /* get rows -- let routine allocate the row array */
  while( (buf = (Ev)FunTableRowGet(fun, NULL, MAXROW, NULL, &got)) ){
    /* point to the i'th row */
    ev = buf + i;
    .... process
  }
  /* write out this batch of rows */
  FunTableRowPut(fun2, buf, got, 0, NULL);
  /* free row data */
  if( buf ) free(buf);
  }
</PRE>

or

<PRE>
  Ev buf, ev;
  ...
  /* get rows -- let routine allocate the row array */
  while( (buf = (Ev)FunTableRowGet(fun, NULL, MAXROW, NULL, &got)) ){
    /* process all rows */
    for(i=0; i&lt;got; i++){
      /* point to the i'th row */
      ev = buf + i;
      ... process
      /* write out this batch of rows with the new column */
      if( dowrite )
        FunTableRowPut(fun2, buf, 1, i, NULL);
    }
    /* free row data */
    if( buf ) free(buf);
  }
</PRE>

<P>
Note that the difference between these calls is that the first one
outputs <B>got</B> rows all at once and therefore passes
<B>idx=0</B> in argument four, so that merging starts at the first raw
input row.  In the second case, a check it made on each row to see
if it needs to be output.  If so, the value of <B>idx</B> is passed as
the value of the <B>i</B> variable which points to the current row
being processed in the batch of input rows.

<P>
As shown above, successive calls to 
<A HREF="./library.html#funtablerowput">FunTableRowPut()</A> will write
rows sequentially. When you are finished writing all rows in a
table, you should call 
<A HREF="./library.html#funflush">FunFlush()</A> to write out the FITS
binary table padding. However, this is not necessary if you
subsequently call FunClose() without doing any other I/O to the FITS
file.

<P>
Note that FunTableRowPut() also can be called as FunEventsPut(), for
backward compatibility.

<!-- =defdoc funparamget funparamget 3 -->

<!-- =section funparamget NAME -->
<H2><A NAME="funparamget">FunParamGet - get a Funtools param value</A></H2>

<!-- =section funparamget SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  int FunParamGetb(Fun fun, char *name, int n, int defval, int *got)

  int FunParamGeti(Fun fun, char *name, int n, int defval, int *got)

  double FunParamGetd(Fun fun, char *name, int n, double defval, int *got)

  char *FunParamGets(Fun fun, char *name, int n, char *defval, int *got)
</PRE>
</B>

<!-- =section funparamget DESCRIPTION -->
<P>
The four routines <B>FunParamGetb()</B>, <B>FunParamGeti()</B>,
<B>FunParamGetd()</B>, and <B>FunParamGets()</B>, return the value of
a FITS header parameter as a boolean, int, double, and string,
respectively. The string returned by <B>FunParamGets()</B> is a malloc'ed
copy of the header value and should be freed when no longer needed.

<P>
The first argument is the Fun handle associated with the FITS header
being accessed. Normally, the header is associated with the FITS
extension that you opened with <B>FunOpen()</B>. However, you can use
FunInfoPut() to specify access of the primary header. In particular,
if you set the FUN_PRIMARYHEADER parameter to 1, then the primary
header is used for all parameter access until the value is reset to
0. For example:
<PRE>
  int val;
  FunParamGeti(fun, "NAXIS", 1, 0, &got);              # current header
  val=1;
  FunInfoPut(fun, FUN_PRIMARYHEADER, &val, 0);         # switch to ...
  FunParamGeti(fun, "NAXIS", 1, 0, &got);              # ... primary header
  FunParamGeti(fun, "NAXIS", 2, 0, &got);              # ... primary header
  val=0;
  FunInfoPut(fun, FUN_PRIMARYHEADER, &val, 0);         # switch back to ...
  FunParamGeti(fun, "NAXIS", 2, 0, &got);              # current header
</PRE>

<P>
Alternatively, you can use the FUN_PRIMARY macro to access parameters
from the primary header on a per-parameter basis:
<PRE>
  FunParamGeti(fun, "NAXIS1", 0, 0, &got);              # current header
  FunParamGeti(FUN_PRIMARY(fun), "NAXIS1", 0, 0, &got); # primary header
</PRE>
<B>NB: FUN_PRIMARY is deprecated.</B>
It makes use of a global parameter and therefore will not not
appropriate for threaded applications, when we make funtools
thread-safe. We recommend use of FunInfoPut() to switch between the
extension header and the primary header.

<P>
For output data, access to the primary header is only possible until
the header is written out, which usually takes place when the first
data are written.

<P>
The second argument is the name of the parameter to access.  The third
<B>n</B> argument, if non-zero, is an integer that will be added as a
suffix to the parameter name.  This makes it easy to use a simple loop
to process parameters having the same root name.  For example, to
gather up all values of TLMIN and TLMAX for each column in a binary
table, you can use:
<PRE>
  for(i=0, got=1; got; i++){
    fun->cols[i]->tlmin = (int)FunParamGeti(fun, "TLMIN", i+1, 0.0, &got);
    fun->cols[i]->tlmax = (int)FunParamGeti(fun, "TLMAX", i+1, 0.0, &got);
  }
</PRE>

<P>
The fourth <B>defval</B> argument is the default value to return if
the parameter does not exist. Note that the data type of this
parameter is different for each specific FunParamGet() call. The final
<B>got</B> argument will be 0 if no param was found. Otherwise the
data type of the parameter is returned as follows: FUN_PAR_UNKNOWN
('u'), FUN_PAR_COMMENT ('c'), FUN_PAR_LOGICAL ('l'), FUN_PAR_INTEGER
('i'), FUN_PAR_STRING ('s'), FUN_PAR_REAL ('r'), FUN_PAR_COMPLEX ('x').

<p>
These routines return the value of the header parameter, or the
specified default value if the header parameter does not exist.  The
returned value is a malloc'ed string and should be freed when no
longer needed.

<P>
By default, <B>FunParamGets()</B> returns the string value of the
named parameter.  However, you can use FunInfoPut() to retrieve the
raw 80-character FITS card instead.  In particular, if you set the
FUN_RAWPARAM parameter to 1, then card images will be returned by
FunParamGets() until the value is reset to 0.

<P>
Alternatively, if the FUN_RAW macro is applied to the name, then the
80-character raw FITS card is returned instead.  
<B>NB: FUN_RAW is deprecated.</B> 
It makes use of a global parameter and therefore will not not
appropriate for threaded applications, when we make funtools
thread-safe. We recommend use of FunInfoPut() to switch between the
extension header and the primary header.

<P>
Note that in addition to the behaviors described above, the
routine <B>FunParamGets()</B> will return the 80 raw characters of the
<B>nth</B> FITS card (including the comment) if <B>name</B> is specified as
NULL and <B>n</B> is positive. For example, to loop through all FITS
header cards in a given extension and print out the raw card, use:
<PRE>
  for(i=1; ;i++){
    if( (s = FunParamGets(fun, NULL, i, NULL, &got)) ){
      fprintf(stdout, "%.80s\n", s);
      free(s);
    }
    else{
      break;
    }
  }
</PRE>

<!-- =defdoc funparamput funparamput 3 -->

<!-- =section funparamput NAME -->
<H2><A NAME="funparamput">FunParamPut - put a Funtools param value</A></H2>

<!-- =section funparamput SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  int FunParamPutb(Fun fun, char *name, int n, int value, char *comm,
                   int append)

  int FunParamPuti(Fun fun, char *name, int n, int value, char *comm,
                   int append)

  int FunParamPutd(Fun fun, char *name, int n, double value, int prec,
                   char *comm, int append)

  int FunParamPuts(Fun fun, char *name, int n, char *value, char *comm,
                   int append)
</PRE>
</B>

<!-- =section funparamput DESCRIPTION -->
<P>
The four routines <B>FunParamPutb()</B>, <B>FunParamPuti()</B>,
<B>FunParamPutd()</B>, and <B>FunParamPuts()</B>, will set the value
of a FITS header parameter as a boolean, int, double, and string,
respectively.

<P>
The first argument is the Fun handle associated with the FITS header
being accessed. Normally, the header is associated with the FITS
extension that you opened with <B>FunOpen()</B>.
However, you can use FunInfoPut() to specify that use of the primary
header. In particular, if you set the FUN_PRIMARYHEADER parameter to
1, then the primary header is used for all parameter access until the
value is reset to 0. For example:
<PRE>
  int val;
  FunParamPuti(fun, "NAXIS1", 0, 10, NULL, 1);       # current header
  val=1;
  FunInfoPut(fun, FUN_PRIMARYHEADER, &val, 0);       # switch to ...
  FunParamPuti(fun, "NAXIS1", 0, 10, NULL, 1);       # primary header
</PRE>
(You also can use the deprecated FUN_PRIMARY macro, to access
parameters from the primary header.)

<p>
The second argument is the <b>name</b> of the parameter.  (
In accordance with FITS standards, the special names <b>COMMENT</b>
and <b>HISTORY</b>, as well as blank names, are output without the "= "
value indicator in columns 9 and 10.

<p>
The third <B>n</B> argument, if non-zero, is an integer that will be
added as a suffix to the parameter name.  This makes it easy to use a
simple loop to process parameters having the same root name.  For
example, to set the values of TLMIN and TLMAX for each column in a
binary table, you can use:
<PRE>
  for(i=0; i&lt;got; i++){
    FunParamPutd(fun, "TLMIN", i+1, tlmin[i], 7, "min column val", 1);
    FunParamPutd(fun, "TLMAX", i+1, tlmax[i], 7, "max column val", 1);
  }
</PRE>

<P>
The fourth <B>defval</B> argument is the value to set.  Note that the
data type of this argument is different for each specific
FunParamPut() call. The <B>comm</B> argument is the comment
string to add to this header parameter. Its value can be NULL.  The
final <B>append</B> argument determines whether the parameter is added
to the header if it does not exist. If set to a non-zero value, the
header parameter will be appended to the header if it does not exist.
If set to 0, the value will only be used to change an existing parameter.

<P>
Note that the double precision routine FunParamPutd() supports an
extra <B>prec</B> argument after the <B>value</B> argument, in order
to specify the precision when converting the double value to ASCII. In
general a 20.[prec] format is used (since 20 characters are alloted to
a floating point number in FITS) as follows: if the double value being
put to the header is less than 0.1 or greater than or equal to
10**(20-2-[prec]), then %20.[prec]e format is used (i.e., scientific
notation); otherwise %20.[prec]f format is used (i.e., numeric
notation).

<P>
As a rule, parameters should be set before writing the table or image.
It is, however, possible to update the value of an <B>existing</B>
parameter after writing an image or table (but not to add a new
one). Such updating only works if the parameter already exists and if
the output file is seekable, i.e. if it is a disk file or is stdout
being redirected to a disk file.

<P>
It is possible to add a new parameter to a header after the data has
been written, but only if space has previously been reserved. To reserve
space, add a blank parameter whose value is the name of the parameter you
eventually will update. Then, when writing the new parameter, specify a 
value of 2 for the append flag. The parameter writing routine will
first look to update an existing parameter, as usual. If an existing
parameter is not found, an appropriately-valued blank parameter will be
searched for and replaced.  For example:
<PRE>
  /* add blank card to be used as a place holder for IPAR1 update */
  FunParamPuts(fun, NULL, 0, "IPAR1", "INTEGER Param", 0);
  ...
  /* write header and data */
  FunTableRowPut(fun, events, got, 0, NULL);
  ...
  /* update param in file after writing data -- note append = 2 here */
  FunParamPuti(fun, "IPAR", 1, 400, "INTEGER Param", 2);
</PRE>

<P>
The parameter routines return a 1 if the routine was successful and a 0 on
failure. In general, the major reason for failure is that you did not
set the append argument to a non-zero value and the parameter did not
already exist in the file.

<!-- =defdoc funinfoget funinfoget 3 -->

<!-- =section funinfoget NAME -->
<H2><A NAME="funinfoget">FunInfoGet - get information from Funtools struct</A></H2>

<!-- =section funinfoget SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  int FunInfoGet(Fun fun, int type, char *addr, ...)
</PRE>
</B>

<!-- =section funinfoget DESCRIPTION -->
<P>
The <B>FunInfoGet()</B> routine returns information culled from the
Funtools structure.  The first argument is the Fun handle from which
information is to be retrieved.  This first required argument is followed
by a variable length list of pairs of arguments. Each pair consists
of an integer representing the type of information to retrieve and the
address where the information is to be stored. The list is terminated by a 0.
The routine returns the number of get actions performed.

<P>
The full list of available information is described below.  Please note
that only a few of these will be useful to most application developers.
For imaging applications, the most important types are:
<PRE>
  FUN_SECT_DIM1   int  /* dim1 for section */
  FUN_SECT_DIM2   int  /* dim2 for section */
  FUN_SECT_BITPIX int  /* bitpix for section */
</PRE>
These would be used to determine the dimensions and data type of image
data retrieved using the
<A HREF="./library.html#funimageget">FunImageGet()</A> routine. For
example:
<PRE>
  /* extract and bin the data section into an image buffer */
  buf = FunImageGet(fun, NULL, NULL);
  /* get required information from funtools structure.
     this should come after the FunImageGet() call, in case the call
     changed sect_bitpix */
  FunInfoGet(fun,
             FUN_SECT_BITPIX,  &bitpix,
             FUN_SECT_DIM1,    &dim1,
             FUN_SECT_DIM2,    &dim2,
             0);
  /* loop through pixels and reset values below limit to value */
  for(i=0; i&lt;dim1*dim2; i++){
    switch(bitpix){
    case 8:
      if( cbuf[i] <= blimit ) cbuf[i] = bvalue;
    ...
  }
</PRE>
It is important to bear in mind that the call to 
<A HREF="./library.html#funimageget">FunImageGet()</A>
can change the value of FUN_SECT_BITPIX (e.g. if "bitpix=n" is passed
in the param list).  Therefore, a call to
<A HREF="./library.html#funinfoget">FunInfoGet()</A>
should be made <B>after</B> the call to 
<A HREF="./library.html#funimageget">FunImageGet()</A>,
in order to retrieve the updated bitpix value.
See the <A HREF="./imblank.c">imblank example code</A> for more
details. 

<P>
It also can be useful to retrieve the World Coordinate System
information from the Funtools structure. Funtools uses the the WCS
Library developed by Doug Mink at SAO, which is available 
<A HREF="ftp://cfa-ftp.harvard.edu/pub/gsc/WCSTools/home.html">here</A>.
(More information about the WCSTools project in general can be found
<A HREF="http://tdc-www.harvard.edu/software/wcstools/">here</A>.)
The <A HREF="./library.html#funopen">FunOpen()</A> routine initializes
two WCS structures that can be used with this WCS Library.
Applications can retrieve either of these two WCS structures using
<B>FunInfoGet()</B>:
<PRE>
  FUN_WCS  struct WorldCoor * /* wcs structure, for image coordinates*/
  FUN_WCS0 struct WorldCoor * /* wcs structure, for physical coordinates */
</PRE>
The structure retrieved by FUN_WCS is a WCS library handle containing
parameters suitable for use with image coordinates, regardless of whether the
data are images or tables. For this structure, the WCS reference point
(CRPIX) has been converted to image coordinates if the underlying file
is a table (and therefore in physical coordinates). You therefore must
ensure that the positions being passed to a routine like pix2wcs are in
image coordinates. The FUN_WCS0 structure has not had its WCS
reference point converted to image coordinates. It therefore is useful
when passing processing physical coordinates from a table.

<P>
Once a WCS structure has been retrieved, it can be used as the first
argument to the WCS library routines. (If the structure is NULL, no
WCS information was contained in the file.) The two important WCS routines
that Funtools uses are:
<PRE>
  #include &lt;wcs.h&gt
  void pix2wcs (wcs,xpix,ypix,xpos,ypos)
    struct WorldCoor *wcs; /* World coordinate system structure */
    double xpix,ypix;      /* x and y coordinates in pixels */
    double *xpos,*ypos;    /* RA and Dec in degrees (returned) */
</PRE>

which converts pixel coordinates to sky coordinates, and:

<PRE>
  void wcs2pix (wcs, xpos, ypos, xpix, ypix, offscl)
    struct WorldCoor *wcs; /* World coordinate system structure */
    double xpos,ypos;      /* World coordinates in degrees */
    double *xpix,*ypix;    /* coordinates in pixels */
    int *offscl;           /* 0 if within bounds, else off scale */
</PRE>
which converts sky coordinates to pixel coordinates. Again, please note
that the wcs structure returned by FUN_WCS assumes that image coordinates
are passed to the pix2wcs routine, while FUN_WCS0 assumes that physical
coordinates are passed.

<P>
Note that funtools.h file automatically includes wcs.h.  An example
program that utilizes these WCS structure to call WCS Library routines
is <A HREF="./twcs.c">twcs.c</A>.

<P>
The following is the complete list of information that can be returned:
<PRE>
  name            type            comment
  ---------       --------        ---------------------------------------------
  FUN_FNAME     char *            /* file name */
  FUN_GIO       GIO               /* gio handle */
  FUN_HEADER    FITSHead          /* fitsy header struct */
  FUN_TYPE      int               /* TY_TABLE,TY_IMAGE,TY_EVENTS,TY_ARRAY */
  FUN_BITPIX    int               /* bits/pixel in file */
  FUN_MIN1      int               /* tlmin of axis1 -- tables */
  FUN_MAX1      int               /* tlmax of axis1 -- tables */
  FUN_MIN2      int               /* tlmin of axis2 -- tables */
  FUN_MAX2      int               /* tlmax of axis2 -- tables */
  FUN_DIM1      int               /* dimension of axis1 */
  FUN_DIM2      int               /* dimension of axis2 */
  FUN_ENDIAN    int               /* 0=little, 1=big endian */
  FUN_FILTER    char *            /* supplied filter */
  FUN_IFUN      FITSHead          /* pointer to reference header */
  FUN_IFUN0     FITSHead          /* same as above, but no reset performed */
  /* image information */
  FUN_DTYPE     int               /* data type for images */
  FUN_DLEN      int               /* length of image in bytes */
  FUN_DPAD      int               /* padding to end of extension */
  FUN_DOBLANK   int               /* was blank keyword defined? */
  FUN_BLANK     int               /* value for blank */
  FUN_SCALED    int               /* was bscale/bzero defined? */
  FUN_BSCALE    double            /* bscale value */
  FUN_BZERO     double            /* bzero value */
  /* table information */
  FUN_NROWS     int               /* number of rows in file (naxis2) */
  FUN_ROWSIZE   int               /* size of user row struct */
  FUN_BINCOLS   char *            /* specified binning columns */
  FUN_OVERFLOW  int               /* overflow detected during binning? */
  /* array information */
  FUN_SKIP      int               /* bytes to skip in array header */
  /* section information */
  FUN_SECT_X0   int               /* low dim1 value of section */
  FUN_SECT_X1   int               /* hi dim1 value of section */
  FUN_SECT_Y0   int               /* low dim2 value of section */
  FUN_SECT_Y1   int               /* hi dim2 value of section */
  FUN_SECT_BLOCK int              /* section block factor */
  FUN_SECT_BTYPE int              /* 's' (sum), 'a' (average) for binning */
  FUN_SECT_DIM1 int               /* dim1 for section */
  FUN_SECT_DIM2 int               /* dim2 for section */
  FUN_SECT_BITPIX int             /* bitpix for section */
  FUN_SECT_DTYPE int              /* data type for section */
  FUN_RAWBUF    char *            /* pointer to raw row buffer */
  FUN_RAWSIZE   int               /* byte size of raw row records */
  /* column  information */
  FUN_NCOL      int               /* number of row columns defined */
  FUN_COLS      FunCol            /* array of row columns */
  /* WCS information */
  FUN_WCS       struct WorldCoor * /* wcs structure, converted for images*/
  FUN_WCS0      struct WorldCoor * /* wcs structure, not converted */
</PRE>

<P>
Row applications would not normally need any of this information.
An example of how these values can be used in more complex programs is
the <A HREF="./evnext.c">evnext example code</A>. In this program, the
time value for each row is changed to be the value of the succeeding
row. The program thus reads the time values for a batch of rows,
changes the time values to be the value for the succeeding row, and
then merges these changed time values back with the other columns to
the output file. It then reads the next batch, etc.

<P>
This does not work for the last row read in each batch, since there
is no succeeding row until the next batch is read. Therefore, the
program saves that last row until it has read the next batch, then
processes the former before starting on the new batch. In order to
merge the last row successfully, the code uses FUN_RAWBUF to save
and restore the raw input data associated with each batch of
rows. Clearly, this requires some information about how funtools
works internally. We are happy to help you write such programs as the
need arises.

<!-- =defdoc funinfoput funinfoput 3 -->

<!-- =section funinfoput NAME -->
<H2><A NAME="funinfoput">FunInfoPut - put information into a Funtools struct</A></H2>

<!-- =section funinfoput SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  int FunInfoPut(Fun fun, int type, char *addr, ...)
</PRE>
</B>

<!-- =section funinfoput DESCRIPTION -->
<P>
The <B>FunInfoPut()</B> routine puts information into a Funtools
structure.  The first argument is the Fun handle from which
information is to be retrieved.  After this first required argument
comes a variable length list of pairs of arguments. Each pair consists
of an integer representing the type of information to store and the
address of the new information to store in the struct. The variable
list is terminated by a 0.  The routine returns the number of put
actions performed.

<P>
The full list of available information is described above with the 
<A HREF="./library.html#funinfoput">FunInfoPut()</A> routine. Although
use of this routine is expected to be uncommon, there is one
important situation in which it plays an essential part: writing
multiple extensions to a single output file.

<P>
For input, multiple extensions are handled by calling 
<A HREF="./library.html#funopen">FunOpen()</A> for each extension to be
processed. When opening multiple inputs, it sometimes is the case that
you will want to process them and then write them (including their
header parameters) to a single output file.  To accomplish this, you
open successive input extensions using 
<A HREF="./library.html#funopen">FunOpen()</A> and then call
<B>FunInfoPut()</B> to set the 
<A HREF="./library.html#refhandle">Funtools reference handle</A>
of the output file to that of the newly opened input extension:
<PRE>
  /* open a new input extension */
  ifun=FunOpen(tbuf, "r", NULL)) )
  /* make the new extension the reference handle for the output file */
  FunInfoPut(ofun, FUN_IFUN, &ifun, 0);
</PRE>

Resetting FUN_IFUN has same effect as when a funtools handle is passed
as the final argument to 
<A HREF="./library.html#funopen">FunOpen()</A>.  The state of the output
file is reset so that a new extension is ready to be written.
Thus, the next I/O call on the output extension will output the
header, as expected.

<P>
For example, in a binary table, after resetting FUN_IFUN you can then
call <A HREF="./library.html#funcolumnselect">FunColumnSelect()</A> to
select the columns for output. When you then call 
<A HREF="./library.html#funimageput">FunImagePut()</A> or <A
HREF="./library.html#funtablerowput">FunTableRowPut()</A>, a new
extension will be written that contains the header parameters from the
reference extension. Remember to call 
<A HREF="./library.html#funflush">FunFlush()</A> to complete output of a
given extension.

<P>
A complete example of this capability is given
in the <A HREF="./evcol.c">evcol example code</A>.
The central algorithm is:
<UL>
<LI> open the output file without a reference handle
<LI> loop: open each input extension in turn
<UL>
<LI> set the reference handle for output to the newly opened input extension
<LI> read the input rows or image and perform processing
<LI> write new rows or image to the output file
<LI> flush the output
<LI> close input extension
</UL>
<LI> close output file
</UL>
Note that <A HREF="./library.html#funflush">FunFlush()</A> is called
after processing each input extension in order to ensure that the
proper padding is written to the output file.  A call to 
<A HREF="./library.html#funflush">FunFlush()</A> also ensures that the
extension header is written to the output file in the case where there
are no rows to output.

<P>
If you wish to output a new extension without using a 
<A HREF="./library.html#refhandle">Funtools reference handle</A>, you can
call FunInfoPut() to reset the FUN_OPS value directly.  For a binary
table, you would then call FunColumnSelect() to set up the columns for
this new extension.
<PRE>
  /* reset the operations performed on this handle */
  int ops=0;
  FunInfoPut(ofun, FUN_OPS, &ops, 0);
  FunColumnSelect(fun, sizeof(EvRec), NULL,
                  "MYCOL", "J", "w", FUN_OFFSET(Ev, mycol),
                  NULL);
</PRE>
Once the FUN_OPS variable has been reset, the next I/O call on the
output extension will output the header, as expected.

<!-- =defdoc funflush funflush 3 -->

<!-- =section funflush NAME -->
<H2><A NAME="funflush">FunFlush - flush data to output file</A></H2>

<!-- =section funflush SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  void FunFlush(Fun fun, char *plist)
</PRE>
</B>

<!-- =section funflush DESCRIPTION -->
<P>
The <B>FunFlush</B> routine will flush data to a FITS output file.  In
particular, it can be called after all rows have been written (using
the <A HREF="./library.html#funtablerowput">FunTableRowPut()</A> routine)
in order to add the null padding that is required to complete a FITS
block. It also should be called after completely writing an image using
<A HREF="./library.html#funimageput">FunImagePut()</A> or after writing
the final row of an image using
<A HREF="./library.html#funtablerowput">FunTableRowPut()</A>.

<P>
The <B>plist</B> (i.e., parameter list) argument is a string
containing one or more comma-delimited <B>keyword=value</B>
parameters.  If the plist string contains the parameter
"copy=remainder" and the file was opened with a reference file, which,
in turn, was opened for extension copying (i.e. the input 
<A HREF="./library.html#funopen">FunOpen()</A> mode also was "c" or "C"),
then FunFlush also will copy the remainder of the FITS extensions from
the input reference file to the output file.  This normally would be
done only at the end of processing.

<P>
Note that <A HREF="./library.html#funflush">FunFlush()</A> is called
with "copy=remainder" in the mode string by FunClose().  This means
that if you close the output file before the reference input file, it
is not necessary to call 
<A HREF="./library.html#funflush">FunFlush()</A> explicitly, unless you
are writing more than one extension.  See the 
<A HREF="./evmerge.c">evmerge example code</A>. However, it is safe to
call <A HREF="./library.html#funflush">FunFlush()</A> more than once
without fear of re-writing either the padding or the copied
extensions.

<P>
In addition, if <A HREF="./library.html#funflush">FunFlush()</A> is
called on an output file with the plist set to "copy=reference" and if
the file was opened with a reference file, the reference extension is
written to the output file.  This mechanism provides a simple way to
copy input extensions to an output file without processing the former.
For example, in the code fragment below, an input extension is set to
be the reference file for a newly opened output extension. If that
reference extension is not a binary table, it is written to the output
file:
<PRE>
  /* process each input extension in turn */
  for(ext=0; ;ext++){
    /* get new extension name */
    sprintf(tbuf, "%s[%d]", argv[1], ext);
    /* open input extension -- if we cannot open it, we are done */
    if( !(ifun=FunOpen(tbuf, "r", NULL)) )
      break;
    /* make the new extension the reference handle for the output file */
    FunInfoPut(ofun, FUN_IFUN, &ifun, 0);
    /* if its not a binary table, just write it out */
    if( !(s=FunParamGets(ifun, "XTENSION", 0, NULL, &got)) || 
      strcmp(s, "BINTABLE")){
      if( s ) free(s);
      FunFlush(ofun, "copy=reference");
      FunClose(ifun);
      continue;
    }
    else{
      /* process binary table */
      ....
    }
  }
</PRE>

<!-- =defdoc funclose funclose 3 -->

<!-- =section funclose NAME -->
<H2><A NAME="funclose">FunClose - close a Funtools data file</A></H2>

<!-- =section funclose SYNOPSIS -->
<B>
<PRE>
  #include &lt;funtools.h&gt;

  void FunClose(Fun fun)
</PRE>
</B>

<!-- =section funclose DESCRIPTION -->
<P>
The <B>FunClose()</B> routine closes a previously-opened Funtools data
file, freeing control structures. If a 
<A HREF="./library.html#refhandle">Funtools reference handle</A>
was passed to
the <A HREF="./library.html#funopen">FunOpen()</A> call for this file,
and if copy mode also was specified for that file, then 
<A HREF="./library.html#funclose">FunClose()</A> also will copy the
remaining extensions from the input file to the output file (if the
input file still is open).  Thus, we recommend always closing the
output Funtools file <B>before</B> the input file.  (Alternatively,
you can call <A HREF="./library.html#funflush">FunFlush()</A>
explicitly).

<!-- =defdoc funref funref 3 -->

<!-- =section funref NAME -->
<H2><A NAME="refhandle">FunRef: the Funtools Reference Handle</A></H2>

<!-- =section funref SYNOPSIS -->
<H2>Summary</H2>
A description of how to use a Funtools reference handle to connect a
Funtools input file to an output file.

<!-- =section funref DESCRIPTION -->
<H2>Description</H2>
<P>
The Funtools reference handle connects a Funtools input file to a
Funtools output file so that parameters (or even whole extensions) can
be copied from the one to the other. To make the connection, the Funtools
handle of the input file is passed to the 
final argument of the
<A HREF="./library.html#funopen">FunOpen()</A> call for the output file:
<PRE>
  if( !(ifun = FunOpen(argv[1], "r", NULL)) )
    gerror(stderr, "could not FunOpen input file: %s\n", argv[1]);
  if( !(ofun = FunOpen(argv[2], "w", ifun)) )
    gerror(stderr, "could not FunOpen output file: %s\n", argv[2]);
</PRE>
It does not matter what type of input or output file (or extension) is
opened, or whether they are the same type. When the output image or
binary table is written using
<A HREF="./library.html#funimageput">FunImagePut()</A>
or
<A HREF="./library.html#funtablerowput">FunTableRowPut()</A>
an appropriate header will be written first, with parameters copied
from the input extension. Of course, invalid parameters will be
removed first, e.g., if the input is a binary table and the output is
an image, then binary table parameters such as TFORM, TUNIT,
etc. parameters will not be copied to the output.

<P>
Use of a reference handle also allows default values to be passed
to
<A HREF="./library.html#funimageput">FunImagePut()</A> in order to
write out an output image with the same dimensions and data type
as the input image. To use the defaults from the input, a value
of 0 is entered for dim1, dim2, and bitpix. For example:
<PRE>
  fun = FunOpen(argv[1], "r", NULL);
  fun2 = FunOpen(argv[2], "w", fun);
  buf = FunImageGet(fun, NULL, NULL);
  ... process image data ...
  FunImagePut(fun2, buf, 0, 0, 0, NULL);
</PRE>
Of course, you often want to get information about the data type
and dimensions of the image for processing. The above code
is equivalent to the following:
<PRE>
  fun = FunOpen(argv[1], "r", NULL);
  fun2 = FunOpen(argv[2], "w", fun);
  buf = FunImageGet(fun, NULL, NULL);
  FunInfoGet(fun, FUN_SECT_DIM1, &dim1, FUN_SECT_DIM2, &dim2, 
             FUN_SECT_BITPIX, &bitpix, 0);
  ... process image data ...
  FunImagePut(fun2, buf, dim1, dim2, bitpix, NULL);
</PRE>

<P>
It is possible to change the reference handle for a given output Funtools
handle using the 
<A HREF="./library.html#funinfoput">FunInfoPut()</A> routine:
<PRE>
  /* make the new extension the reference handle for the output file */
  FunInfoPut(fun2, FUN_IFUN, &fun, 0);
</PRE>
When this is done, Funtools specially resets the output file to start
a new output extension, which is connected to the new input reference
handle. You can use this mechanism to process multiple input extensions
into a single output file, by successively opening the former and
setting the reference handle for the latter. For example:
<PRE>
  /* open a new output FITS file */
  if( !(fun2 = FunOpen(argv[2], "w", NULL)) )
    gerror(stderr, "could not FunOpen output file: %s\n", argv[2]);
  /* process each input extension in turn */
  for(ext=0; ;ext++){
    /* get new extension name */
    sprintf(tbuf, "%s[%d]", argv[1], ext);
    /* open it -- if we cannot open it, we are done */
    if( !(fun=FunOpen(tbuf, "r", NULL)) )
      break;
    /* make the new extension the reference handle for the output file */
    FunInfoPut(fun2, FUN_IFUN, &fun, 0);
    ... process ...
    /* flush output extension (write padding, etc.) */
    FunFlush(fun2, NULL);
    /* close the input extension */
    FunClose(fun);
  }
</PRE>
In this example, the output file is opened first. Then each successive
input extension is opened, and the output reference handle is set to
the newly opened input handle. After data processing is performed, the
output extension is flushed and the input extension is closed, in
preparation for the next input extension.
<P>
Finally, a reference handle can be used to copy other extensions from
the input file to the output file.  Copy of other extensions is
controlled by adding a "C" or "c" to the mode string of the
<A HREF="./library.html#funopen">FunOpen()</A>
call <B>of the input reference file</B>.  If "C" is specified, then
other extensions are <B>always</B> copied (i.e., copy is forced by the
application).  If "c" is used, then other extensions are copied if the
user requests copying by adding a plus sign "+" to the extension name
in the bracket specification.  For example, the <B>funtable</B>
program utilizes user-specified "c" mode so that the second example
below will copy all extensions:
<PRE>
  # copy only the EVENTS extension
  csh> funtable "test.ev[EVENTS,circle(512,512,10)]" foo.ev
  # copy ALL extensions
  csh> funtable "test.ev[EVENTS+,circle(512,512,10)]" foo.ev
</PRE>
When extension copy is specified in the input file, the call to
<A HREF="./library.html#funopen">FunOpen()</A>
on the input file delays the actual file open until the output file
also is opened (or until I/O is performed on the input file, which
ever happens first). Then, when the output file is opened, the input
file is also opened and input extensions are copied to the output
file, up to the specific extension being opened. Processing of input
and output extensions then proceed.
<P>
When extension processing is complete, the remaining extensions need to
be copied from input to output. This can be done explicitly, using the
<A HREF="./library.html#funflush">FunFlush()</A>
call with the "copy=remaining" plist:
<PRE>
  FunFlush(fun, "copy=remaining");
</PRE>
Alternatively, this will happen automatically, if the output file
is closed <B>before</B> the input file:
<PRE>
  /* we could explicitly flush remaining extensions that need copying */
  /* FunFlush(fun2, "copy=remaining"); */
  /* but if we close output before input, end flush is done automatically  */
  FunClose(fun2);
  FunClose(fun);
</PRE>

<!-- =section funlib SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funopen SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funimageget SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funimageput SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funimagerowget SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funimagerowput SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funcolumnselect SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funcolumnactivate SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funcolumnlookup SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funtablerowget SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funtablerowput SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funparamget SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funparamput SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funinfoget SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funinfoput SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funflush SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funclose SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =section funref SEE ALSO -->
<!-- =text See funtools(n) for a list of Funtools help pages -->
<!-- =stop -->

<P>
<A HREF="./help.html">Go to Funtools Help Index</A>

<H5>Last updated: December 1, 2005</H5>

</BODY>
</HTML>