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32 .\" @(#)fopen.3 8.1 (Berkeley) 6/4/93
33 .\" $FreeBSD: src/lib/libc/stdio/fopen.3,v 1.20 2007/01/09 00:28:06 imp Exp $
34 .\" $DragonFly: src/lib/libc/stdio/fopen.3,v 1.4 2007/04/04 18:36:55 swildner Exp $
43 .Nd stream open functions
49 .Fn fopen "const char * restrict path" "const char * restrict mode"
51 .Fn fdopen "int fildes" "const char *mode"
53 .Fn freopen "const char *path" "const char *mode" "FILE *stream"
58 opens the file whose name is the string pointed to by
60 and associates a stream with it.
64 points to a string beginning with one of the following
65 sequences (Additional characters may follow these sequences.):
66 .Bl -tag -width indent
68 Open text file for reading.
69 The stream is positioned at the beginning of the file.
71 Open for reading and writing.
72 The stream is positioned at the beginning of the file.
74 Truncate to zero length or create text file for writing.
75 The stream is positioned at the beginning of the file.
77 Open for reading and writing.
78 The file is created if it does not exist, otherwise it is truncated.
79 The stream is positioned at the beginning of the file.
82 The file is created if it does not exist.
83 The stream is positioned at the end of the file.
84 Subsequent writes to the file will always end up at the then current
85 end of file, irrespective of any intervening
89 Open for reading and writing.
90 The file is created if it does not exist.
91 The stream is positioned at the end of the file.
92 Subsequent writes to the file will always end up at the then current
93 end of file, irrespective of any intervening
100 string can also include the letter ``b'' either as a third character or
101 as a character between the characters in any of the two-character strings
103 This is strictly for compatibility with
105 and has no effect; the ``b'' is ignored.
107 Any created files will have mode
120 as modified by the process'
124 Reads and writes may be intermixed on read/write streams in any order,
125 and do not require an intermediate seek as in previous versions of
127 This is not portable to other systems, however;
130 a file positioning function intervene between output and input, unless
131 an input operation encounters end-of-file.
135 function associates a stream with the existing file descriptor,
138 of the stream must be compatible with the mode of the file descriptor.
139 When the stream is closed via
147 opens the file whose name is the string pointed to by
149 and associates the stream pointed to by
152 The original stream (if it exists) is closed.
155 argument is used just as in the
164 attempts to re-open the file associated with
167 The new mode must be compatible with the mode that the stream was originally
169 .Bl -bullet -offset indent
171 Streams originally opened with mode
173 can only be reopened with that same mode.
175 Streams originally opened with mode
177 can be reopened with the same mode, or mode
180 Streams originally opened with mode
182 can be reopened with the same mode, or mode
185 Streams originally opened with mode
190 can be reopened with any mode.
193 The primary use of the
196 is to change the file associated with a
198 .Dv ( stderr , stdin ,
202 Upon successful completion
212 is returned and the global variable
214 is set to indicate the error.
235 may also fail and set
237 for any of the errors specified for the routine
243 may also fail and set
245 for any of the errors specified for the routine
251 may also fail and set
253 for any of the errors specified for the routine
259 may also fail and set
261 for any of the errors specified for the routines