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diff --git a/man3/fopen.3 b/man3/fopen.3 new file mode 100644 index 000000000..7ecf6695e --- /dev/null +++ b/man3/fopen.3 @@ -0,0 +1,235 @@ +.\" Copyright (c) 1990, 1991 The Regents of the University of California. +.\" All rights reserved. +.\" +.\" This code is derived from software contributed to Berkeley by +.\" Chris Torek and the American National Standards Committee X3, +.\" on Information Processing Systems. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)fopen.3 6.8 (Berkeley) 6/29/91 +.\" +.\" Converted for Linux, Mon Nov 29 15:22:01 1993, faith@cs.unc.edu +.\" Modified, aeb, 960421, 970806 +.\" Modified, joey, aeb, 2002-01-03 +.\" +.TH FOPEN 3 2002-01-03 "BSD MANPAGE" "Linux Programmer's Manual" +.SH NAME +fopen, fdopen, freopen \- stream open functions +.SH SYNOPSIS +.B #include <stdio.h> +.sp +.BI "FILE *fopen(const char *" path ", const char *" mode ); +.br +.BI "FILE *fdopen(int " fildes ", const char *" mode ); +.br +.BI "FILE *freopen(const char *" path ", const char *" mode ", FILE *" stream ); +.SH DESCRIPTION +The +.B fopen +function opens the file whose name is the string pointed to by +.I path +and associates a stream with it. +.PP +The argument +.I mode +points to a string beginning with one of the following sequences +(Additional characters may follow these sequences.): +.TP +.B r +Open text file for reading. The stream is positioned at the beginning of +the file. +.TP +.B r+ +Open for reading and writing. The stream is positioned at the beginning of +the file. +.TP +.B w +Truncate file to zero length or create text file for writing. The stream +is positioned at the beginning of the file. +.TP +.B w+ +Open for reading and writing. The file is created if it does not exist, +otherwise it is truncated. The stream is positioned at the beginning of +the file. +.TP +.B a +Open for appending (writing at end of file). The file is created +if it does not exist. The stream is positioned at the end of the file. +.TP +.B a+ +Open for reading and appending (writing at end of file). The file +is created if it does not exist. +The stream is positioned at the end of the file. +.PP +The +.I mode +string can also include the letter ``b'' either as a last character or as +a character between the characters in any of the two-character strings +described above. This is strictly for compatibility with ANSI X3.159-1989 +(``ANSI C'') and has no effect; the ``b'' is ignored on all POSIX +conforming systems, including Linux. +(Other systems may treat text files and binary files differently, +and adding the ``b'' may be a good idea if you do I/O to a binary +file and expect that your program may be ported to non-Unix +environments.) +.PP +Any created files will have mode +.BR S_IRUSR \&| S_IWUSR \&| S_IRGRP \&| S_IWGRP \&| S_IROTH \&| S_IWOTH +(0666), as modified by the process' umask value (see +.BR umask (2)). +.PP +Reads and writes may be intermixed on read/write streams in any order. +Note that ANSI C requires that a file positioning function intervene +between output and input, unless an input operation encounters end-of-file. +(If this condition is not met, then a read is allowed to return the +result of writes other than the most recent.) +Therefore it is good practice (and indeed sometimes necessary +under Linux) to put an +.B fseek +or +.B fgetpos +operation between write and read operations on such a stream. This +operation may be an apparent no-op (as in \fIfseek(..., 0L, +SEEK_CUR)\fR called for its synchronizing side effect. +.PP +Opening a file in append mode (\fBa\fR as the first character of +.IR mode ) +causes all subsequent write operations to this stream to occur +at end-of-file, as if preceded by an +.RS +fseek(stream,0,SEEK_END); +.RE +call. +.PP +The +.B fdopen +function associates a stream with the existing file descriptor, +.IR fildes . +The +.I mode +of the stream (one of the values "r", "r+", "w", "w+", "a", "a+") +must be compatible with the mode of the file descriptor. +The file position indicator of the new stream is set to that +belonging to +.IR fildes , +and the error and end-of-file indicators are cleared. +Modes "w" or "w+" do not cause truncation of the file. +The file descriptor is not dup'ed, and will be closed when +the stream created by +.B fdopen +is closed. +The result of applying +.B fdopen +to a shared memory object is undefined. +.PP +The +.B freopen +function opens the file whose name is the string pointed to by +.I path +and associates the stream pointed to by +.I stream +with it. The original stream (if it exists) is closed. The +.I mode +argument is used just as in the +.B fopen +function. The primary use of the +.B freopen +function is to change the file associated with a standard text stream +.IR "" ( stderr ", " stdin ", or " stdout ). +.SH "RETURN VALUE" +Upon successful completion +.BR fopen , +.B fdopen +and +.B freopen +return a +.B FILE +pointer. Otherwise, +.B NULL +is returned and the global variable +.I errno +is set to indicate the error. +.SH ERRORS +.TP +.B EINVAL +The +.I mode +provided to +.BR fopen , +.BR fdopen , +or +.B freopen +was invalid. +.PP +The +.BR fopen , +.B fdopen +and +.B freopen +functions may also fail and set +.I errno +for any of the errors specified for the routine +.BR malloc (3). +.PP +The +.B fopen +function may also fail and set +.I errno +for any of the errors specified for the routine +.BR open (2). +.PP +The +.B fdopen +function may also fail and set +.I errno +for any of the errors specified for the routine +.BR fcntl (2). +.PP +The +.B freopen +function may also fail and set +.I errno +for any of the errors specified for the routines +.BR open (2), +.BR fclose (3) +and +.BR fflush (3). +.SH "CONFORMING TO" +The +.B fopen +and +.B freopen +functions conform to ANSI X3.159-1989 (``ANSI C''). The +.B fdopen +function conforms to IEEE Std1003.1-1988 (``POSIX.1''). +.SH "SEE ALSO" +.BR open (2), +.BR fclose (3), +.BR fileno (3) |