1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
NAME
fopen - open a file
SYNOPSIS
fopen(filename, mode)
TYPES
filename string
mode string
return file
DESCRIPTION
This function opens the file named filename. A file can be
opened for either reading, writing, or appending. The mode
is controlled by the mode flag as follows:
allow allow file is positioned file(*)
mode reading writing truncated at mode
---- ------- ------- --------- --------- ----
r Y N N beginning text
rb Y N N beginning binary
r+ Y N N beginning text
r+b Y N N beginning binary
rb+ Y N N beginning binary
w N Y Y beginning text
wb N Y Y beginning binary
w+ Y Y Y beginning text
w+b Y Y Y beginning binary
wb+ Y Y Y beginning binary
a N Y Y end text
ab N Y Y end binary
a+ Y Y Y end text
a+b Y Y Y end binary
ab+ Y Y Y end binary
(*) NOTE on 'b' / binary/text mode:
The 'b' or fopen binary mode has no effect on POSIX / Linux
/ Un*x-like systems. On those systems a text file is the
same as a binary file (as it should be for any modern-day
operating system). Adding 'b' to an fopen has no effect
and is ignored.
Some non-POSIX systems such as MS Windows treat text files
and binary files differently. In text mode MS Windows consider
"\r\n" an end-of-line character. On an Apple MAC, the
text mode end-of-line character is "\r".
Names of files are subject to ~ expansion just like the C or
Korn shell. For example, the file name:
~/lib/fizzbin
refers to the file 'fizzbin' under the directory lib located
in your home directory. The file name:
~chongo/was_here
refers to the a file 'was_here' under the home directory of
the user 'chongo'.
If the open is successful, a value of type 'file' will be returned.
You can use the 'isfile' function to test the return value to see
if the open succeeded. You should assign the return value of fopen
to a variable for later use. File values can be copied to more than
one variable, and using any of the variables with the same file value
will produce the same results.
Standard input, standard output and standard error are always opened
and cannot be closed.
The truth value of an opened file is TRUE.
If the open is unsuccessful, the numeric value of errno is returned.
You can the strerror() builtin to determine what the errno number means.
EXAMPLE
; fd = fopen("/etc/motd", "r")
; print fd
"/etc/motd"
; fd
FILE 3 "/etc/motd" (reading, pos 0)
; outfile = fopen("~/tmp/output", "w")
; print outfile
"~/tmp/output"
; outfile
FILE 4 "~/tmp/output" (writing, pos 0)
; badfile = fopen("not_a_file", "r");
; if (!isfile(badfile)) {
;; printf("error(%d): %s\n", errno(badfile), strerror(badfile));
;; }
error(2): No such file or directory
LIMITS
none
LINK LIBRARY
none
SEE ALSO
errno, fclose, feof, ferror, fflush, fgetc, fgetline, fgets, files, fopen,
fprintf, fputc, fputs, fseek, fsize, ftell, isfile, printf, prompt,
fpathopen, strerror
## Copyright (C) 1999-2006,2021 Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
## distributed with calc under the filename COPYING-LGPL. You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
##
## Under source code control: 1994/10/27 03:04:17
## File existed as early as: 1994
##
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
|
