.nr yr \n(yr+1900
.af mo 01
.af dy 01
.TH NETCDF 3 "1997-04-18" "Printed: \n(yr-\n(mo-\n(dy" "UNIDATA LIBRARY FUNCTIONS"
.SH NAME
netcdf \- Unidata Network Common Data Form (netCDF) library, version 3 interface
.SH SYNOPSIS
.ft B
.na
.nh
#include "netcdf.h"
.sp

cc ... -lnetcdf

.ad
.hy
.SH "LIBRARY VERSION"
.LP
This document describes version 3 of Unidata netCDF data-access interface
for the C programming language.
.HP
\fBconst char* nc_inq_libvers()\fR
.sp
Returns a string identifying the version of the netCDF library, and
when it was built, like: "3.1a of Aug 22 1996 12:57:47 $".
.LP
The RCS \fBident(1)\fP command will find a string like
"$\|Id: @\|(#) netcdf library version 3.1a of Sep  6 1996 15:56:26 $"
in the library. The SCCS \fBwhat(1)\fP command will find a string like
"netcdf library version 3.1a of Aug 23 1996 16:07:40 $".
.SH "RETURN VALUES"
.LP
All netCDF functions (except
\fBnc_inq_libvers(\|)\fR and \fBnc_strerror(\|)\fR) return an integer status.
This behavior replaces the
\fBncerr()\fR function
used in previous versions of the library.
If this returned status value is not equal to
\fBNC_NOERR\fR (zero), it
indicates that an error occurred. The possible status values are defined in 
system include file <errno.h> and in "netcdf.h".
.HP
\fBconst char* nc_strerror(int \fIstatus\fP)\fR
.sp
Returns a string textual translation of the \fIstatus\fP
value, like "Attribute or variable name contains illegal characters"
or "No such file or directory".
.HP
\fBint nc_create(const char \fIpath\fP[], int \fIcmode\fP, 
int* \fIncid\fP)\fR
.sp
(Corresponds to \fBnccreate(\|)\fR in version 2)
.sp
Creates a new netCDF dataset at \fIpath\fP,
returning a netCDF ID in \fIncid\fP.
The argument \fIcmode\fP may include the bitwise-or
of the following flags:
\fBNC_NOCLOBBER\fR
to protect existing datasets (default
silently blows them away),
\fBNC_SHARE\fR
for synchronous dataset updates
(default is to buffer accesses), and
\fBNC_LOCK\fR
(not yet implemented).
When a netCDF dataset is created, is is opened
\fBNC_WRITE\fR.
The new netCDF dataset is in define mode.
\fBNC_64BIT_OFFSET\fR.
to create a file in the 64-bit offset  
(as opposed to classic , the default). 64-bit 
offset  allows the creation of very large files 
with far fewer restrictions than netCDF classic , 
but can only be read by the netCDF library version 3.6 
or greater. Users are cautioned that files that use the 64-bit offset 
will not be recognized by netCDF applications linked to an earlier
version of the netCDF library than 3.6.  Applications linked to
version 3.6 or later will be able to transparently access either the
classic  or 64-bit offset .
.HP
\fBint nc__create(const char \fIpath\fP[], int \fIcmode\fP, size_t \fIinitialsize\fP, size_t* \fIchunksize\fP, int* \fIncid\fP)\fR
.sp
Like \fBnc_create(\|)\fR but has additional performance tuning parameters.
.sp
The argument \fIinitialsize\fP sets the initial size of the file at
creation time.
.sp
See \fBnc__open(\|)\fR below for an explanation of the \fIchunksize\fP
parameter.
.HP
\fBint nc_open(const char \fIpath\fP[], int \fImode\fP, int* \fIncid\fP)\fR
.sp
(Corresponds to \fBncopen(\|)\fR in version 2)
.sp
Opens a existing netCDF dataset at \fIpath\fP
returning a netCDF ID
in \fIncid\fP.
The type of access is described by the \fImode\fP parameter,
which may include the bitwise-or
of the following flags:
\fBNC_WRITE\fR
for read-write access (default
read-only),
\fBNC_SHARE\fR
for synchronous dataset updates (default is
to buffer accesses), and
\fBNC_LOCK\fR
(not yet implemented).
.HP
\fBint nc__open(const char \fIpath\fP[], int \fImode\fP, size_t* \fIchunksize\fP, int* \fIncid\fP)\fR
.sp
Like \fBnc_open(\|)\fR but has an additional performance tuning parameter.
.sp
The argument referenced by \fIchunksize\fP controls a space versus time
tradeoff, memory allocated in the netcdf library versus number of system
calls.
Because of internal requirements, the value may not be set to exactly
the value requested.
The actual value chosen is returned by reference.
Using the value \fBNC_SIZEHINT_DEFAULT\fR causes the library to choose a
default.
How the system choses the default depends on the system.
On many systems, the "preferred I/O block size" is available from the 
\fBstat()\fR system call, \fBstruct stat\fR member \fBst_blksize\fR.
If this is available it is used. Lacking that, twice the system pagesize
is used.
Lacking a call to discover the system pagesize, we just set default
chunksize to 8192.
.sp
The chunksize is a property of a given open netcdf descriptor
\fIncid\fP, it is not a persistent property of the netcdf dataset.
.HP
\fBint nc_redef(int \fIncid\fP)\fR
.sp
(Corresponds to \fBncredef(\|)\fR in version 2)
.sp
Puts an open netCDF dataset into define mode, 
so dimensions, variables, and attributes can be added or renamed and 
attributes can be deleted.
.HP
\fBint nc_enddef(int \fIncid\fP)\fR
.sp
(Corresponds to \fBncendef(\|)\fR in version 2)
.sp
Takes an open netCDF dataset out of define mode.
The changes made to the netCDF dataset
while it was in define mode are checked and committed to disk if no
problems occurred.  Some data values may be written as well,
see "VARIABLE PREFILLING" below.
After a successful call, variable data can be read or written to the dataset.
.HP
\fBint nc__enddef(int \fIncid\fP, size_t \fIh_minfree\fP, size_t \fIv_align\fP, size_t \fIv_minfree\fP, size_t \fIr_align\fP)\fR
.sp
Like \fBnc_enddef(\|)\fR but has additional performance tuning parameters.
.sp
Caution: this function exposes internals of the netcdf version 1 file
format.
It may not be available on future netcdf implementations.
.sp
The current netcdf file format has three sections,
the "header" section, the data section for fixed size variables, and
the data section for variables which have an unlimited dimension (record
variables).
The header begins at the beginning of the file. The index
(offset) of the beginning of the other two sections is contained in the
header. Typically, there is no space between the sections. This causes
copying overhead to accrue if one wishes to change the size of the
sections,
as may happen when changing names of things, text attribute values,
adding
attributes or adding variables. Also, for buffered i/o, there may be
advantages
to aligning sections in certain ways.
.sp
The minfree parameters allow one to control costs of future calls
to \fBnc_redef(\|)\fR, \fBnc_enddef(\|)\fR by requesting that \fIminfree\fP bytes be
available at the end of the section.
The \fIh_minfree\fP parameter sets the pad
at the end of the "header" section. The \fIv_minfree\fP parameter sets
the pad at the end of the data section for fixed size variables.
.sp
The align parameters allow one to set the alignment of the beginning of
the corresponding sections. The beginning of the section is rounded up
to an index which is a multiple of the align parameter. The flag value
\fBNC_ALIGN_CHUNK\fR tells the library to use the chunksize (see above)
as the align parameter.
The \fIv_align\fP parameter controls the alignment of the beginning of
the data section for fixed size variables.
The \fIr_align\fP parameter controls the alignment of the beginning of
the data section for variables which have an unlimited dimension (record
variables).
.sp
The file format requires mod 4 alignment, so the align parameters
are silently rounded up to multiples of 4. The usual call,
\fBnc_enddef(\fIncid\fP)\fR
is equivalent to
\fBnc__enddef(\fIncid\fP, 0, 4, 0, 4)\fR.
.sp
The file format does not contain a "record size" value, this is
calculated from the sizes of the record variables. This unfortunate fact
prevents us from providing minfree and alignment control of the
"records"
in a netcdf file. If you add a variable which has an unlimited
dimension,
the third section will always be copied with the new variable added.
.HP
\fBint nc_sync(int \fIncid\fP)\fR
.sp
(Corresponds to \fBncsync(\|)\fR in version 2)
.sp
Unless the
\fBNC_SHARE\fR
bit is set in
\fBnc_open(\|)\fR or \fBnc_create(\|)\fR,
accesses to the underlying netCDF dataset are
buffered by the library. This function synchronizes the state of
the underlying dataset and the library.
This is done automatically by
\fBnc_close(\|)\fR and \fBnc_enddef(\|)\fR.
.HP
\fBint nc_abort(int \fIncid\fP)\fR
.sp
(Corresponds to \fBncabort(\|)\fR in version 2)
.sp
You don't need to call this function.
This function is called automatically by
\fBnc_close(\|)\fR
if the netCDF was in define mode and something goes wrong with the commit.
If the netCDF dataset isn't in define mode, then this function is equivalent to
\fBnc_close(\|)\fR.
If it is called after
\fBnc_redef(\|)\fR,
but before
\fBnc_enddef(\|)\fR,
the new definitions are not committed and the dataset is closed.
If it is called after
\fBnc_create(\|)\fR
but before
\fBnc_enddef(\|)\fR,
the dataset disappears.
.HP
\fBint nc_close(int \fIncid\fP)\fR
.sp
(Corresponds to
\fBncclose(\|)\fR in version 2)
.sp
Closes an open netCDF dataset.
If the dataset is in define mode,
\fBnc_enddef(\|)\fR
will be called before closing.
After a dataset is closed, its ID may be reassigned to another dataset.
.HP
\fBint nc_inq(int \fIncid\fP, int* \fIndims\fP, int* \fInvars\fP,
int* \fInatts\fP, int* \fIunlimdimid\fP)\fR
.HP
\fBint nc_inq_ndims(int \fIncid\fP, int* \fIndims\fP)\fR
.HP
\fBint nc_inq_nvars(int \fIncid\fP, int* \fInvars\fP)\fR
.HP
\fBint nc_inq_natts(int \fIncid\fP, int* \fInatts\fP)\fR
.HP
\fBint nc_inq_unlimdim(int \fIncid\fP, int* \fIunlimdimid\fP)\fR
.HP
\fBint nc_inq_format(int \fIncid\fP, int* \fIformatn\fP)\fR
.sp
(Replace \fBncinquire(\|)\fR in version 2)
.sp
Use these functions to find out what is in a netCDF dataset.
Upon successful return,
\fIndims\fP will contain  the
number of dimensions defined for this netCDF dataset,
\fInvars\fP will contain the number of variables,
\fInatts\fP will contain the number of attributes, and
\fIunlimdimid\fP will contain the
dimension ID of the unlimited dimension if one exists, or
-1 otherwise.
\fIformatn\fP will contain the version number of the dataset <>, one of
\fBNC_FORMAT_CLASSIC\fR, \fBNC_FORMAT_64BIT\fR, \fBNC_FORMAT_NETCDF4\fR, or
\fBNC_FORMAT_NETCDF4_CLASSIC\fR.
If any of the
return parameters is a \fBNULL\fR pointer, then the corresponding information
will not be returned; hence, no space need be allocated for it.
.HP
\fBint nc_def_dim(int \fIncid\fP, const char \fIname\fP[], size_t \fIlen\fP, int* \fIdimid\fP)\fR
.sp
(Corresponds to \fBncdimdef(\|)\fR in version 2)
.sp
Adds a new dimension to an open netCDF dataset, which must be 
in define mode.
\fIname\fP is the dimension name.
If \fIdimid\fP is not a \fBNULL\fR pointer then upon successful completion \fIdimid\fP will contain the dimension ID of the newly created dimension.
.HP
\fBint nc_inq_dimid(int \fIncid\fP, const char \fIname\fP[], int* \fIdimid\fP)\fR
.sp
(Corresponds to \fBncdimid(\|)\fR in version 2)
.sp
Given a dimension name, returns the ID of a netCDF dimension in \fIdimid\fP.
.HP
\fBint nc_inq_dim(int \fIncid\fP, int \fIdimid\fP, char \fIname\fP[], size_t* \fIlen\fP)\fR
.HP
\fBint nc_inq_dimname(int \fIncid\fP, int \fIdimid\fP, char \fIname\fP[])\fR
.HP
\fBint nc_inq_dimlen(int \fIncid\fP, int \fIdimid\fP, size_t* \fIlen\fP)\fR
.sp
(Replace \fBncdiminq(\|)\fR in version 2)
.sp
Use these functions to find out about a dimension.
If either the \fIname\fP
argument or \fIlen\fP argument is a \fBNULL\fR pointer, then
the associated information will not be returned.  Otherwise,
\fIname\fP should be  big enough (\fBNC_MAX_NAME\fR)
to hold the dimension name as the name will be copied into your storage.
The length return parameter, \fIlen\fP
will contain the size of the dimension.
For the unlimited dimension, the returned length is the current
maximum value used for writing into any of the variables which use
the dimension.
.HP
\fBint nc_rename_dim(int \fIncid\fP, int \fIdimid\fP, const char \fIname\fP[])\fR
.sp
(Corresponds to \fBncdimrename(\|)\fR in version 2)
.sp
Renames an existing dimension in an open netCDF dataset.
If the new name is longer than the old name, the netCDF dataset must be in 
define mode.
You cannot rename a dimension to have the same name as another dimension.
.HP
\fBint nc_def_var(int \fIncid\fP, const char \fIname\fP[], nc_type \fIxtype\fP, int \fIndims\fP, const int \fIdimids\fP[], int* \fIvarid\fP)\fR
.sp
(Corresponds to \fBncvardef(\|)\fR in version 2)
.sp
Adds a new variable to a netCDF dataset. The netCDF must be in define mode.
If not \fBNULL\fR, then \fIvarid\fP will be set to the netCDF variable ID.
.HP
\fBint nc_inq_varid(int \fIncid\fP, const char \fIname\fP[], int* \fIvarid\fP)\fR
.sp
(Corresponds to \fBncvarid(\|)\fR in version 2)
.sp
Returns the ID of a netCDF variable in \fIvarid\fP given its name.
.HP
\fBint nc_inq_var(int \fIncid\fP, int \fIvarid\fP, char \fIname\fP[], nc_type* \fIxtype\fP, int* \fIndims\fP, int \fIdimids\fP[],
int* \fInatts\fP)\fR
.HP
\fBint nc_inq_varname(int \fIncid\fP, int \fIvarid\fP, char \fIname\fP[])\fR
.HP
\fBint nc_inq_vartype(int \fIncid\fP, int \fIvarid\fP, nc_type* \fIxtype\fP)\fR
.HP
\fBint nc_inq_varndims(int \fIncid\fP, int \fIvarid\fP, int* \fIndims\fP)\fR
.HP
\fBint nc_inq_vardimid(int \fIncid\fP, int \fIvarid\fP, int \fIdimids\fP[])\fR
.HP
\fBint nc_inq_varnatts(int \fIncid\fP, int \fIvarid\fP, int* \fInatts\fP)\fR
.sp
(Replace \fBncvarinq(\|)\fR in version 2)
.sp
Returns information about a netCDF variable, given its ID.
If any of the
return parameters (\fIname\fP, \fIxtype\fP, \fIndims\fP, \fIdimids\fP, or
\fInatts\fP) is a \fBNULL\fR pointer, then the corresponding information
will not be returned; hence, no space need be allocated for it.
.HP
\fBint nc_rename_var(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[])\fR
.sp
(Corresponds to \fBncvarrename(\|)\fR in version 2)
.sp
Changes the name of a netCDF variable.
If the new name is longer than the old name, the netCDF must be in define mode.
You cannot rename a variable to have the name of any existing variable.
.HP
\fBint nc_put_var_text(int \fIncid\fP, int \fIvarid\fP, const char \fIout\fP[])\fR
.HP
\fBint nc_put_var_uchar(int \fIncid\fP, int \fIvarid\fP, const unsigned char \fIout\fP[])\fR
.HP
\fBint nc_put_var_schar(int \fIncid\fP, int \fIvarid\fP, const signed char \fIout\fP[])\fR
.HP
\fBint nc_put_var_short(int \fIncid\fP, int \fIvarid\fP, const short \fIout\fP[])\fR
.HP
\fBint nc_put_var_int(int \fIncid\fP, int \fIvarid\fP, const int \fIout\fP[])\fR
.HP
\fBint nc_put_var_long(int \fIncid\fP, int \fIvarid\fP, const long \fIout\fP[])\fR
.HP
\fBint nc_put_var_float(int \fIncid\fP, int \fIvarid\fP, const float \fIout\fP[])\fR
.HP
\fBint nc_put_var_double(int \fIncid\fP, int \fIvarid\fP, const double \fIout\fP[])\fR
.sp
(Replace \fBncvarput(\|)\fR in version 2)
.sp
Writes an entire netCDF variable (i.e. all the values).  The netCDF
dataset must be open and in data mode.  The type of the data is
specified in the function name, and it is converted to the external
type of the specified variable, if possible, otherwise an
\fBNC_ERANGE\fR error is returned. Note that rounding is not performed
during the conversion. Floating point numbers are truncated when
converted to integers.
.HP
\fBint nc_get_var_text(int \fIncid\fP, int \fIvarid\fP, char \fIin\fP[])\fR
.HP
\fBint nc_get_var_uchar(int \fIncid\fP, int \fIvarid\fP, unsigned char \fIin\fP[])\fR
.HP
\fBint nc_get_var_schar(int \fIncid\fP, int \fIvarid\fP, signed char \fIin\fP[])\fR
.HP
\fBint nc_get_var_short(int \fIncid\fP, int \fIvarid\fP, short \fIin\fP[])\fR
.HP
\fBint nc_get_var_int(int \fIncid\fP, int \fIvarid\fP, int \fIin\fP[])\fR
.HP
\fBint nc_get_var_long(int \fIncid\fP, int \fIvarid\fP, long \fIin\fP[])\fR
.HP
\fBint nc_get_var_float(int \fIncid\fP, int \fIvarid\fP, float \fIin\fP[])\fR
.HP
\fBint nc_get_var_double(int \fIncid\fP, int \fIvarid\fP, double \fIin\fP[])\fR
.sp
(Replace \fBncvarget(\|)\fR in version 2)
.sp
Reads an entire netCDF variable (i.e. all the values).
The netCDF dataset must be open and in data mode.  
The data is converted from the external type of the specified variable,
if necessary, to the type specified in the function name.  If conversion is
not possible, an \fBNC_ERANGE\fR error is returned.
.HP
\fBint nc_put_var1_text(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], char \fI*out\fP)\fR
.HP
\fBint nc_put_var1_uchar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], unsigned char \fI*out\fP)\fR
.HP
\fBint nc_put_var1_schar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], signed char \fI*out\fP)\fR
.HP
\fBint nc_put_var1_short(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], short \fI*out\fP)\fR
.HP
\fBint nc_put_var1_int(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], int \fI*out\fP)\fR
.HP
\fBint nc_put_var1_long(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], long \fI*out\fP)\fR
.HP
\fBint nc_put_var1_float(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], float \fI*out\fP)\fR
.HP
\fBint nc_put_var1_double(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], double \fI*out\fP)\fR
.sp
(Replace \fBncvarput1(\|)\fR in version 2)
.sp
Puts a single data value into a variable at the position \fIindex\fP of an
open netCDF dataset that is in data mode.  The type of the data is
specified in the function name, and it is converted to the external type
of the specified variable, if possible, otherwise an \fBNC_ERANGE\fR
error is returned.
.HP
\fBint nc_get_var1_text(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], char* \fIin\fP)\fR
.HP
\fBint nc_get_var1_uchar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], unsigned char* \fIin\fP)\fR
.HP
\fBint nc_get_var1_schar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], signed char* \fIin\fP)\fR
.HP
\fBint nc_get_var1_short(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], short* \fIin\fP)\fR
.HP
\fBint nc_get_var1_int(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], int* \fIin\fP)\fR
.HP
\fBint nc_get_var1_long(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], long* \fIin\fP)\fR
.HP
\fBint nc_get_var1_float(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], float* \fIin\fP)\fR
.HP
\fBint nc_get_var1_double(int \fIncid\fP, int \fIvarid\fP, const size_t \fIindex\fP[], double* \fIin\fP)\fR
.sp
(Replace \fBncvarget1(\|)\fR in version 2)
.sp
Gets a single data value from a variable at the position \fIindex\fP
of an open netCDF dataset that is in data mode.  
The data is converted from the external type of the specified variable,
if necessary, to the type specified in the function name.  If conversion is
not possible, an \fBNC_ERANGE\fR error is returned.
.HP
\fBint nc_put_vara_text(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const char \fIout\fP[])\fR
.HP
\fBint nc_put_vara_uchar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const unsigned char \fIout\fP[])\fR
.HP
\fBint nc_put_vara_schar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const signed char \fIout\fP[])\fR
.HP
\fBint nc_put_vara_short(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const short \fIout\fP[])\fR
.HP
\fBint nc_put_vara_int(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const int \fIout\fP[])\fR
.HP
\fBint nc_put_vara_long(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const long \fIout\fP[])\fR
.HP
\fBint nc_put_vara_float(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const float \fIout\fP[])\fR
.HP
\fBint nc_put_vara_double(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const double \fIout\fP[])\fR
.sp
(Replace \fBncvarput(\|)\fR in version 2)
.sp
Writes an array section of values into a netCDF variable of an open
netCDF dataset, which must be in data mode.  The array section is specified
by the \fIstart\fP and \fIcount\fP vectors, which give the starting index
and count of values along each dimension of the specified variable.
The type of the data is
specified in the function name and is converted to the external type
of the specified variable, if possible, otherwise an \fBNC_ERANGE\fR
error is returned.
.HP
\fBint nc_get_vara_text(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], char \fIin\fP[])\fR
.HP
\fBint nc_get_vara_uchar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], unsigned char \fIin\fP[])\fR
.HP
\fBint nc_get_vara_schar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], signed char \fIin\fP[])\fR
.HP
\fBint nc_get_vara_short(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], short \fIin\fP[])\fR
.HP
\fBint nc_get_vara_int(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], int \fIin\fP[])\fR
.HP
\fBint nc_get_vara_long(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], long \fIin\fP[])\fR
.HP
\fBint nc_get_vara_float(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], float \fIin\fP[])\fR
.HP
\fBint nc_get_vara_double(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], double \fIin\fP[])\fR
.sp
(Corresponds to \fBncvarget(\|)\fR in version 2)
.sp
Reads an array section of values from a netCDF variable of an open
netCDF dataset, which must be in data mode.  The array section is specified
by the \fIstart\fP and \fIcount\fP vectors, which give the starting index
and count of values along each dimension of the specified variable.
The data is converted from the external type of the specified variable,
if necessary, to the type specified in the function name.  If conversion is
not possible, an \fBNC_ERANGE\fR error is returned.
.HP
\fBint nc_put_vars_text(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], const char \fIout\fP[])\fR
.HP
\fBint nc_put_vars_uchar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], const unsigned char \fIout\fP[])\fR
.HP
\fBint nc_put_vars_schar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], const signed char \fIout\fP[])\fR
.HP
\fBint nc_put_vars_short(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], const short \fIout\fP[])\fR
.HP
\fBint nc_put_vars_int(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], const int \fIout\fP[])\fR
.HP
\fBint nc_put_vars_long(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], const long \fIout\fP[])\fR
.HP
\fBint nc_put_vars_float(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], const float \fIout\fP[])\fR
.HP
\fBint nc_put_vars_double(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], const double \fIout\fP[])\fR
.sp
(Corresponds to \fBncvarputg(\|)\fR in version 2)
.sp
These functions are used for \fIstrided output\fP, which is like the
array section output described above, except that
the sampling stride (the interval between accessed values) is
specified for each dimension.
For an explanation of the sampling stride
vector, see COMMON ARGUMENTS DESCRIPTIONS below.
.HP
\fBint nc_get_vars_text(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], char \fIin\fP[])\fR
.HP
\fBint nc_get_vars_uchar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], unsigned char \fIin\fP[])\fR
.HP
\fBint nc_get_vars_schar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], signed char \fIin\fP[])\fR
.HP
\fBint nc_get_vars_short(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], short \fIin\fP[])\fR
.HP
\fBint nc_get_vars_int(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], int \fIin\fP[])\fR
.HP
\fBint nc_get_vars_long(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], long \fIin\fP[])\fR
.HP
\fBint nc_get_vars_float(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], float \fIin\fP[])\fR
.HP
\fBint nc_get_vars_double(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], double \fIin\fP[])\fR
.sp
(Corresponds to \fBncvargetg(\|)\fR in version 2)
.sp
These functions are used for \fIstrided input\fP, which is like the
array section input described above, except that 
the sampling stride (the interval between accessed values) is
specified for each dimension.
For an explanation of the sampling stride
vector, see COMMON ARGUMENTS DESCRIPTIONS below.
.HP
\fBint nc_put_varm_text(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, const char \fIout\fP[])\fR
.HP
\fBint nc_put_varm_uchar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, const unsigned char \fIout\fP[])\fR
.HP
\fBint nc_put_varm_schar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, const signed char \fIout\fP[])\fR
.HP
\fBint nc_put_varm_short(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, const short \fIout\fP[])\fR
.HP
\fBint nc_put_varm_int(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, const int \fIout\fP[])\fR
.HP
\fBint nc_put_varm_long(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, const long \fIout\fP[])\fR
.HP
\fBint nc_put_varm_float(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, const float \fIout\fP[])\fR
.HP
\fBint nc_put_varm_double(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, const double \fIout\fP[])\fR
.sp
(Corresponds to \fBncvarputg(\|)\fR in version 2)
.sp
These functions are used for \fImapped output\fP, which is like
strided output described above, except that an additional index mapping
vector is provided to specify the in-memory arrangement of the data
values.
For an explanation of the index
mapping vector, see COMMON ARGUMENTS DESCRIPTIONS below.
.HP
\fBint nc_get_varm_text(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, char \fIin\fP[])\fR
.HP
\fBint nc_get_varm_uchar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, unsigned char \fIin\fP[])\fR
.HP
\fBint nc_get_varm_schar(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, signed char \fIin\fP[])\fR
.HP
\fBint nc_get_varm_short(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, short \fIin\fP[])\fR
.HP
\fBint nc_get_varm_int(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, int \fIin\fP[])\fR
.HP
\fBint nc_get_varm_long(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, long \fIin\fP[])\fR
.HP
\fBint nc_get_varm_float(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, float \fIin\fP[])\fR
.HP
\fBint nc_get_varm_double(int \fIncid\fP, int \fIvarid\fP, const size_t \fIstart\fP[], const size_t \fIcount\fP[], const size_t \fIstride\fP[], \fIimap\fP, double \fIin\fP[])\fR
.sp
(Corresponds to \fBncvargetg(\|)\fR in version 2)
.sp
These functions are used for \fImapped input\fP, which is like
strided input described above, except that an additional index mapping
vector is provided to specify the in-memory arrangement of the data
values.
For an explanation of the index
mapping vector, see COMMON ARGUMENTS DESCRIPTIONS below.
.HP
\fBint nc_put_att_text(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], nc_type \fIxtype\fP, size_t \fIlen\fP, const char \fIout\fP[])\fR
.HP
\fBint nc_put_att_uchar(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], nc_type \fIxtype\fP, size_t \fIlen\fP, const unsigned char \fIout\fP[])\fR
.HP
\fBint nc_put_att_schar(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], nc_type \fIxtype\fP, size_t \fIlen\fP, const signed char \fIout\fP[])\fR
.HP
\fBint nc_put_att_short(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], nc_type \fIxtype\fP, size_t \fIlen\fP, const short \fIout\fP[])\fR
.HP
\fBint nc_put_att_int(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], nc_type \fIxtype\fP, size_t \fIlen\fP, const int \fIout\fP[])\fR
.HP
\fBint nc_put_att_long(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], nc_type \fIxtype\fP, size_t \fIlen\fP, const long \fIout\fP[])\fR
.HP
\fBint nc_put_att_float(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], nc_type \fIxtype\fP, size_t \fIlen\fP, const float \fIout\fP[])\fR
.HP
\fBint nc_put_att_double(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], nc_type \fIxtype\fP, size_t \fIlen\fP, const double \fIout\fP[])\fR
.sp
(Replace \fBncattput(\|)\fR in version 2)
.sp
Unlike variables, attributes do not have 
separate functions for defining and writing values.
This family of functions defines a new attribute with a value or changes
the value of an existing attribute.
If the attribute is new, or if the space required to
store the attribute value is greater than before,
the netCDF dataset must be in define mode.
The parameter \fIlen\fP is the number of values from \fIout\fP to transfer.
It is often one, except that for
\fBnc_put_att_text(\|)\fR it will usually be
\fBstrlen(\fIout\fP)\fR.
.sp
For these functions, the type component of the function name refers to
the in-memory type of the value, whereas the \fIxtype\fP argument refers to the
external type for storing the value.  An \fBNC_ERANGE\fR
error results if
a conversion between these types is not possible.  In this case the value
is represented with the appropriate fill-value for the associated 
external type.
.HP
\fBint nc_inq_attname(int \fIncid\fP, int \fIvarid\fP, int \fIattnum\fP, char \fIname\fP[])\fR
.sp
(Corresponds to \fBncattname(\|)\fR in version 2)
.sp
Gets the
name of an attribute, given its variable ID and attribute number.
This function is useful in generic applications that
need to get the names of all the attributes associated with a variable,
since attributes are accessed by name rather than number in all other
attribute functions.  The number of an attribute is more volatile than
the name, since it can change when other attributes of the same variable
are deleted.  The attributes for each variable are numbered
from 0 (the first attribute) to
\fInvatts\fP-1,
where \fInvatts\fP is
the number of attributes for the variable, as returned from a call to
\fBnc_inq_varnatts(\|)\fR.
If the \fIname\fP parameter is a \fBNULL\fR pointer, no name will be
returned and no space need be allocated.
.HP
\fBint nc_inq_att(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], nc_type* \fIxtype\fP, size_t* \fIlen\fP)\fR
.HP
\fBint nc_inq_attid(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], int* \fIattnum\fP)\fR
.HP
\fBint nc_inq_atttype(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], nc_type* \fIxtype\fP)\fR
.HP
\fBint nc_inq_attlen(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], size_t* \fIlen\fP)\fR
.sp
(Corresponds to \fBncattinq(\|)\fR in version 2)
.sp
These functions return information about a netCDF attribute,
given its variable ID and name.  The information returned is the
external type in \fIxtype\fP
and the number of elements in the attribute as \fIlen\fP.
If any of the return arguments is a \fBNULL\fR pointer,
the specified information will not be returned.
.HP
\fBint nc_copy_att(int \fIncid\fP, int \fIvarid_in\fP, const char \fIname\fP[], int \fIncid_out\fP, int \fIvarid_out\fP)\fR
.sp
(Corresponds to \fBncattcopy(\|)\fR in version 2)
.sp
Copies an
attribute from one netCDF dataset to another.  It can also be used to
copy an attribute from one variable to another within the same netCDF.
\fIncid_in\fP is the netCDF ID of an input netCDF dataset from which the
attribute will be copied.
\fIvarid_in\fP
is the ID of the variable in the input netCDF dataset from which the
attribute will be copied, or \fBNC_GLOBAL\fR
for a global attribute.
\fIname\fP
is the name of the attribute in the input netCDF dataset to be copied.
\fIncid_out\fP
is the netCDF ID of the output netCDF dataset to which the attribute will be 
copied.
It is permissible for the input and output netCDF ID's to be the same.  The
output netCDF dataset should be in define mode if the attribute to be
copied does not already exist for the target variable, or if it would
cause an existing target attribute to grow.
\fIvarid_out\fP
is the ID of the variable in the output netCDF dataset to which the attribute will
be copied, or \fBNC_GLOBAL\fR to copy to a global attribute.
.HP
\fBint nc_rename_att(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], const char \fInewname\fP[])\fR
.sp
(Corresponds to \fBncattrename(\|)\fR
.sp
Changes the
name of an attribute.  If the new name is longer than the original name,
the netCDF must be in define mode.  You cannot rename an attribute to
have the same name as another attribute of the same variable.
\fIname\fP is the original attribute name.
\fInewname\fP
is the new name to be assigned to the specified attribute.  If the new name
is longer than the old name, the netCDF dataset must be in define mode.
.HP
\fBint nc_del_att(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[])\fR
.sp
(Corresponds to \fBncattdel(\|)\fR in version 2)
.sp
Deletes an attribute from a netCDF dataset.  The dataset must be in
define mode.
.HP
\fBint nc_get_att_text(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], char \fIin\fP[])\fR
.HP
\fBint nc_get_att_uchar(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], unsigned char \fIin\fP[])\fR
.HP
\fBint nc_get_att_schar(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], signed char \fIin\fP[])\fR
.HP
\fBint nc_get_att_short(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], short \fIin\fP[])\fR
.HP
\fBint nc_get_att_int(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], int \fIin\fP[])\fR
.HP
\fBint nc_get_att_long(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], long \fIin\fP[])\fR
.HP
\fBint nc_get_att_float(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], float \fIin\fP[])\fR
.HP
\fBint nc_get_att_double(int \fIncid\fP, int \fIvarid\fP, const char \fIname\fP[], double \fIin\fP[])\fR
.sp
(Replace \fBncattget(\|)\fR in version 2)
.sp
Gets the value(s) of a netCDF attribute, given its
variable ID and name.  Converts from the external type to the type
specified in
the function name, if possible, otherwise returns an \fBNC_ERANGE\fR
error.
All elements of the vector of attribute
values are returned, so you must allocate enough space to hold
them.  If you don't know how much space to reserve, call
\fBnc_inq_attlen(\|)\fR
first to find out the length of the attribute.
.SH "COMMON ARGUMENT DESCRIPTIONS"
.LP
In this section we define some common arguments which are used in the 
"FUNCTION DESCRIPTIONS" section.
.TP
int \fIncid\fP
is the netCDF ID returned from a previous, successful call to
\fBnc_open(\|)\fR or \fBnc_create(\|)\fR
.TP
char \fIname\fP[]
is the name of a dimension, variable, or attribute. The names of 
dimensions, variables and attributes consist of arbitrary
sequences of alphanumeric characters (as well as underscore '_',
period '.' and hyphen '-'), beginning with a letter or
underscore. (However names commencing with underscore are reserved for
system use.) Case is significant in netCDF names. A zero-length name
is not allowed.
As an input argument, 
it shall be a pointer to a 0-terminated string; as an output argument, it 
shall be the address of a buffer in which to hold such a string.
The maximum allowable number of characters 
(excluding the terminating 0) is \fBNC_MAX_NAME\fR.
.TP
nc_type \fIxtype\fP
specifies the external data type of a netCDF variable or attribute and
is one of the following:
\fBNC_BYTE\fR, \fBNC_CHAR\fR, \fBNC_SHORT\fR, \fBNC_INT\fR, 
\fBNC_FLOAT\fR, or \fBNC_DOUBLE\fR.
These are used to specify 8-bit integers,
characters, 16-bit integers, 32-bit integers, 32-bit IEEE floating point
numbers, and 64-bit IEEE floating-point numbers, respectively.
(\fBNC_INT\fR corresponds to \fBNC_LONG\fR in version 2, to specify a
32-bit integer).
.TP
int \fIdimids\fP[]
is a vector of dimension ID's and defines the shape of a netCDF variable.
The size of the vector shall be greater than or equal to the
rank (i.e. the number of dimensions) of the variable (\fIndims\fP).
The vector shall be ordered by the speed with which a dimension varies:
\fIdimids\fP[\fIndims\fP-1]
shall be the dimension ID of the most rapidly
varying dimension and
\fIdimids\fP[0]
shall be the dimension ID of the most slowly
varying dimension.
The maximum possible number of
dimensions for a variable is given by the symbolic constant
\fBNC_MAX_VAR_DIMS\fR.
.TP
int \fIdimid\fP
is the ID of a netCDF dimension.
netCDF dimension ID's are allocated sequentially from the 
non-negative
integers beginning with 0.
.TP
int \fIndims\fP
is either the total number of dimensions in a netCDF dataset or the rank
(i.e. the number of dimensions) of a netCDF variable.
The value shall not be negative or greater than the symbolic constant 
\fBNC_MAX_VAR_DIMS\fR.
.TP
int \fIvarid\fP
is the ID of a netCDF variable or (for the attribute-access functions) 
the symbolic constant
\fBNC_GLOBAL\fR,
which is used to reference global attributes.
netCDF variable ID's are allocated sequentially from the 
non-negative
integers beginning with 0.
.TP
int* \fInatts\fP
is the number of global attributes in a netCDF dataset  for the
\fBnc_inquire(\|)\fR
function or the number
of attributes associated with a netCDF variable for the
\fBnc_varinq(\|)\fR
function.
.TP
const size_t \fIindex\fP[]
specifies the indicial coordinates of the netCDF data value to be accessed.
The indices start at 0;
thus, for example, the first data value of a
two-dimensional variable is (0,0).
The size of the vector shall be at least the rank of the associated
netCDF variable and its elements shall correspond, in order, to the
variable's dimensions.
.TP
const size_t \fIstart\fP[]
specifies the starting point
for accessing a netCDF variable's data values
in terms of the indicial coordinates of 
the corner of the array section.
The indices start at 0;
thus, the first data
value of a variable is (0, 0, ..., 0).
The size of the vector shall be at least the rank of the associated
netCDF variable and its elements shall correspond, in order, to the
variable's dimensions.
.TP
const size_t \fIcount\fP[]
specifies the number of indices selected along each dimension of the
array section.
Thus, to access a single value, for example, specify \fIcount\fP as
(1, 1, ..., 1).
Note that, for strided I/O, this argument must be adjusted
to be compatible with the \fIstride\fP and \fIstart\fP arguments so that 
the interaction of the
three does not attempt to access an invalid data co-ordinate.
The elements of the
\fIcount\fP vector correspond, in order, to the variable's dimensions.
.TP
const size_t \fIstride\fP[]
specifies the sampling interval along each dimension of the netCDF
variable.   The elements of the stride vector correspond, in order,
to the netCDF variable's dimensions (\fIstride\fP[0])
gives the sampling interval along the most slowly 
varying dimension of the netCDF variable).  Sampling intervals are
specified in type-independent units of elements (a value of 1 selects
consecutive elements of the netCDF variable along the corresponding
dimension, a value of 2 selects every other element, etc.).
A \fBNULL\fR stride argument is treated as (1, 1, ... , 1).
.TP
\fIimap\fP
specifies the mapping between the dimensions of a netCDF variable and
the in-memory structure of the internal data array.  The elements of
the index mapping vector correspond, in order, to the netCDF variable's
dimensions (\fIimap\fP[0] gives the distance
between elements of the internal array corresponding to the most
slowly varying dimension of the netCDF variable).
Distances between elements are specified in type-independent units of
elements (the distance between internal elements that occupy adjacent
memory locations is 1 and not the element's byte-length as in netCDF 2).
A \fBNULL\fR pointer means the memory-resident values have
the same structure as the associated netCDF variable.
.SH "VARIABLE PREFILLING"
.LP
By default, the netCDF interface sets the values of
all newly-defined variables of finite length (i.e. those that do not have
an unlimited, dimension) to the type-dependent fill-value associated with each 
variable.  This is done when \fBnc_enddef(\|)\fR
is called.  The
fill-value for a variable may be changed from the default value by
defining the attribute `\fB_FillValue\fR' for the variable.  This
attribute must have the same type as the variable and be of length one.
.LP
Variables with an unlimited dimension are also prefilled, but on
an `as needed' basis.  For example, if the first write of such a
variable is to position 5, then
positions
0 through 4
(and no others)
would be set to the fill-value at the same time.
.LP
This default prefilling of data values may be disabled by
or'ing the
\fBNC_NOFILL\fR
flag into the mode parameter of \fBnc_open(\|)\fR or \fBnc_create(\|)\fR,
or, by calling the function \fBnc_set_fill(\|)\fR
with the argument \fBNC_NOFILL\fR.
For variables that do not use the unlimited dimension,
this call must
be made before
\fBnc_enddef(\|)\fR.
For variables that
use the unlimited dimension, this call
may be made at any time.
.LP
One can obtain increased performance of the netCDF interface by using 
this feature, but only at the expense of requiring the application to set
every single data value.  The performance
enhancing behavior of this function is dependent on the particulars of
the implementation and dataset format.
The flag value controlled by \fBnc_set_fill(\|)\fR
is per netCDF ID,
not per variable or per write. 
Allowing this to change affects the degree to which
a program can be effectively parallelized.
Given all of this, we state that the use
of this feature may not be available (or even needed) in future
releases. Programmers are cautioned against heavy reliance upon this
feature.
.HP
\fBint nc_setfill(int \fIncid\fP, int \fIfillmode\fP, int* \fIold_fillemode\fP)\fR
.sp
(Corresponds to \fBncsetfill(\|)\fR in version 2)
.sp
Determines whether or not variable prefilling will be done (see 
above).
The netCDF dataset shall be writable.
\fIfillmode\fP is either \fBNC_FILL\fR
to enable prefilling (the
default) or \fBNC_NOFILL\fR
to disable prefilling.
This function returns the previous setting in \fIold_fillmode\fP.
.SH "MPP FUNCTION DESCRIPTIONS"
.LP
Additional functions for use on SGI/Cray MPP machines (_CRAYMPP).
These are used to set and inquire which PE is the base for MPP
for a particular netCDF. These are only relevant when
using the SGI/Cray ``global''
Flexible File I/O layer and desire to have
only a subset of PEs to open the specific netCDF file.
For technical reasons, these functions are available on all platforms.
On a platform other than SGI/Cray MPP, it is as if
only processor available were processor 0.
.LP
To use this feature, you need to specify a communicator group and call
\fBglio_group_mpi(\|)\fR or \fBglio_group_shmem(\|)\fR prior to the netCDF
\fBnc_open(\|)\fR and \fBnc_create(\|)\fR calls.
.HP
\fBint nc__create_mp(const char \fIpath\fP[], int \fIcmode\fP, size_t \fIinitialsize\fP, int \fIpe\fP, size_t* \fIchunksize\fP, int* \fIncid\fP)\fR
.sp
Like \fBnc__create(\|)\fR but allows the base PE to be set.
.sp
The argument \fIpe\fP sets the base PE at creation time. In the MPP
environment, \fBnc__create(\|)\fR and \fBnc_create(\|)\fR set the base PE to processor
zero by default.
.HP
\fBint nc__open_mp(const char \fIpath\fP[], int \fImode\fP, int \fIpe\fP, size_t* \fIchunksize\fP, int* \fIncid\fP)\fR
.sp
Like \fBnc__open(\|)\fR but allows the base PE to be set.
The argument \fIpe\fP sets the base PE at creation time. In the MPP
environment, \fBnc__open(\|)\fR and \fBnc_open(\|)\fR set the base PE to processor
zero by default.
.HP
\fBint nc_inq_base_pe(int \fIncid\fP, int* \fIpe\fP)\fR
.sp
Inquires of the netCDF dataset which PE is being used as the base for MPP use.
This is safe to use at any time.
.HP
\fBint nc_set_base_pe(int \fIncid\fP, int \fIpe\fP)\fR
.sp
Resets the base PE for the netCDF dataset.
Only perform this operation when the affected communicator group
synchronizes before and after the call.
This operation is very risky and should only be contemplated
under only the most extreme cases.
.SH "ENVIRONMENT VARIABLES"
.TP 4
.B NETCDF_FFIOSPEC
Specifies the Flexible File I/O buffers for netCDF I/O when executing
under the UNICOS operating system (the variable is ignored on other
operating systems).
An appropriate specification can greatly increase the efficiency of 
netCDF I/O -- to the extent that it can actually surpass FORTRAN binary 
I/O.
This environment variable has been made a little more generalized,
such that other FFIO option specifications can now be added.
The default specification is \fBbufa:336:2\fP,
unless a current FFIO specification is in operation,
which will be honored.
See UNICOS Flexible File I/O for more information.
.SH "MAILING-LISTS"
.LP
Both a mailing list and a digest are available for
discussion of the netCDF interface and announcements about netCDF bugs,
fixes, and enhancements.
To begin or change your subscription to either the mailing-list or the
digest, send one of the following in the body (not
the subject line) of an email message to "majordomo@unidata.ucar.edu".
Use your email address in place of \fIjdoe@host.inst.domain\fP.
.sp
To subscribe to the netCDF mailing list:
.RS
\fBsubscribe netcdfgroup \fIjdoe@host.inst.domain\fR
.RE
To unsubscribe from the netCDF mailing list:
.RS
\fBunsubscribe netcdfgroup \fIjdoe@host.inst.domain\fR
.RE
To subscribe to the netCDF digest:
.RS
\fBsubscribe netcdfdigest \fIjdoe@host.inst.domain\fR
.RE
To unsubscribe from the netCDF digest:
.RS
\fBunsubscribe netcdfdigest \fIjdoe@host.inst.domain\fR
.RE
To retrieve the general introductory information for the mailing list:
.RS
\fBinfo netcdfgroup\fR
.RE
To get a synopsis of other majordomo commands:
.RS
\fBhelp\fR
.RE
.SH "SEE ALSO"
.LP
.BR ncdump (1),
.BR ncgen (1),
.BR netcdf (3),
.BR netcdf_f77 (3),
.BR netcdf_f90 (3)).
.LP
\fInetCDF User's Guide\fP, published
by the Unidata Program Center, University Corporation for Atmospheric
Research, located in Boulder, Colorado.