+++ /dev/null
-.\" Copyright (c) 1990, 1991, 1993
-.\" 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.
-.\" 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 8.1 (Berkeley) 6/4/93
-.\" $FreeBSD: src/lib/libc/stdio/fopen.3,v 1.21 2009/09/09 19:38:19 ed Exp $
-.\"
-.Dd January 26, 2003
-.Dt FOPEN 3
-.Os
-.Sh NAME
-.Nm fdopen ,
-.Nm fopen ,
-.Nm freopen
-.Nd stream open functions
-.Sh LIBRARY
-.Lb libc
-.Sh SYNOPSIS
-.In stdio.h
-.Ft FILE *
-.Fo fdopen
-.Fa "int fildes"
-.Fa "const char *mode"
-.Fc
-.Ft FILE *
-.Fo fopen
-.Fa "const char *restrict filename"
-.Fa "const char *restrict mode"
-.Fc
-.Ft FILE *
-.Fo freopen
-.Fa "const char *restrict filename"
-.Fa "const char *restrict mode"
-.Fa "FILE *restrict stream"
-.Fc
-.Sh DESCRIPTION
-The
-.Fn fopen
-function
-opens the file whose name is the string pointed to by
-.Fa filename
-and associates a stream with it.
-.Pp
-The argument
-.Fa mode
-points to a string beginning with one of the following
-sequences (Additional characters may follow these sequences.):
-.Bl -tag -width indent
-.It Dq Li r
-Open text file for reading.
-The stream is positioned at the beginning of the file.
-.It Dq Li r+
-Open for reading and writing.
-The stream is positioned at the beginning of the file.
-.It Dq Li w
-Truncate to zero length or create text file for writing.
-The stream is positioned at the beginning of the file.
-.It Dq Li 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.
-.It Dq Li a
-Open for writing.
-The file is created if it does not exist.
-The stream is positioned at the end of the file.
-Subsequent writes to the file will always end up at the then current
-end of file, irrespective of any intervening
-.Xr fseek 3
-or similar.
-.It Dq Li a+
-Open for reading and writing.
-The file is created if it does not exist.
-The stream is positioned at the end of the file.
-Subsequent writes to the file will always end up at the then current
-end of file, irrespective of any intervening
-.Xr fseek 3
-or similar.
-.El
-.Pp
-The
-.Fa mode
-string can also include the letter ``b'' either as last character or
-as a character between the characters in any of the two-character strings
-described above.
-This is strictly for compatibility with
-.St -isoC
-and has no effect; the ``b'' is ignored.
-.Pp
-Finally, as an extension to the standards (and thus may not be portable),
-.Fa mode
-string may end with the letter ``x'', which insists on creating a new file
-when used with ``w'' or ``a''.
-If
-.Fa path
-exists, then an error is returned (this is the equivalent of specifying
-.Dv O_EXCL
-with
-.Xr open 2 ) .
-.Pp
-Any created files will have mode
-.Pf \\*q Dv S_IRUSR
-\&|
-.Dv S_IWUSR
-\&|
-.Dv S_IRGRP
-\&|
-.Dv S_IWGRP
-\&|
-.Dv S_IROTH
-\&|
-.Dv S_IWOTH Ns \\*q
-.Pq Li 0666 ,
-as modified by the process'
-umask value (see
-.Xr umask 2 ) .
-.Pp
-Reads and writes may be intermixed on read/write streams in any order,
-and do not require an intermediate seek as in previous versions of
-.Em stdio .
-This is not portable to other systems, however;
-.Tn ANSI C
-requires that
-a file positioning function intervene between output and input, unless
-an input operation encounters end-of-file.
-.Pp
-The
-.Fn fdopen
-function associates a stream with the existing file descriptor,
-.Fa fildes .
-The mode
-of the stream must be compatible with the mode of the file descriptor.
-When the stream is closed via
-.Xr fclose 3 ,
-.Fa fildes
-is closed also.
-.Pp
-The
-.Fn freopen
-function
-opens the file whose name is the string pointed to by
-.Fa filename
-and associates the stream pointed to by
-.Fa stream
-with it.
-The original stream (if it exists) is closed.
-The
-.Fa mode
-argument is used just as in the
-.Fn fopen
-function.
-.Pp
-If the
-.Fa filename
-argument is
-.Dv NULL ,
-.Fn freopen
-attempts to re-open the file associated with
-.Fa stream
-with a new mode.
-The new mode must be compatible with the mode that the stream was originally
-opened with:
-.Bl -bullet -offset indent
-.It
-Streams originally opened with mode
-.Dq Li r
-can only be reopened with that same mode.
-.It
-Streams originally opened with mode
-.Dq Li a
-can be reopened with the same mode, or mode
-.Dq Li w .
-.It
-Streams originally opened with mode
-.Dq Li w
-can be reopened with the same mode, or mode
-.Dq Li a .
-.It
-Streams originally opened with mode
-.Dq Li r+ ,
-.Dq Li w+ ,
-or
-.Dq Li a+
-can be reopened with any mode.
-.El
-.Pp
-The primary use of the
-.Fn freopen
-function
-is to change the file associated with a
-standard text stream
-.Dv ( stderr , stdin ,
-or
-.Dv stdout ) .
-.Sh RETURN VALUES
-Upon successful completion
-.Fn fopen ,
-.Fn fdopen ,
-and
-.Fn freopen
-return a
-.Tn FILE
-pointer.
-Otherwise,
-.Dv NULL
-is returned and the global variable
-.Va errno
-is set to indicate the error.
-.Sh ERRORS
-.Bl -tag -width Er
-.It Bq Er EINVAL
-The
-.Fa mode
-argument
-to
-.Fn fopen ,
-.Fn fdopen ,
-or
-.Fn freopen
-was invalid.
-.El
-.Pp
-The
-.Fn fopen ,
-.Fn fdopen
-and
-.Fn freopen
-functions
-may also fail and set
-.Va errno
-for any of the errors specified for the routine
-.Xr malloc 3 .
-.Pp
-The
-.Fn fopen
-function
-may also fail and set
-.Va errno
-for any of the errors specified for the routine
-.Xr open 2 .
-.Pp
-The
-.Fn fdopen
-function
-may also fail and set
-.Va errno
-for any of the errors specified for the routine
-.Xr fcntl 2 .
-.Pp
-The
-.Fn freopen
-function
-may also fail and set
-.Va errno
-for any of the errors specified for the routines
-.Xr open 2 ,
-.Xr fclose 3
-and
-.Xr fflush 3 .
-.Sh SEE ALSO
-.Xr open 2 ,
-.Xr fclose 3 ,
-.Xr fileno 3 ,
-.Xr fseek 3 ,
-.Xr funopen 3
-.Sh STANDARDS
-The
-.Fn fopen
-and
-.Fn freopen
-functions
-conform to
-.St -isoC .
-The
-.Fn fdopen
-function
-conforms to
-.St -p1003.1-88 .
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