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/*
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* and/or other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
/*
FUNCTION
<<fileno>>, <<fileno_unlocked>>---return file descriptor associated with stream
INDEX
fileno
INDEX
fileno_unlocked
SYNOPSIS
#include <stdio.h>
int fileno(FILE *<[fp]>);
#define _BSD_SOURCE
#include <stdio.h>
int fileno_unlocked(FILE *<[fp]>);
DESCRIPTION
You can use <<fileno>> to return the file descriptor identified by <[fp]>.
<<fileno_unlocked>> is a non-thread-safe version of <<fileno>>.
<<fileno_unlocked>> may only safely be used within a scope
protected by flockfile() (or ftrylockfile()) and funlockfile(). This
function may safely be used in a multi-threaded program if and only
if they are called while the invoking thread owns the (FILE *)
object, as is the case after a successful call to the flockfile() or
ftrylockfile() functions. If threads are disabled, then
<<fileno_unlocked>> is equivalent to <<fileno>>.
RETURNS
<<fileno>> returns a non-negative integer when successful.
If <[fp]> is not an open stream, <<fileno>> returns -1.
PORTABILITY
<<fileno>> is not part of ANSI C.
POSIX requires <<fileno>>.
<<fileno_unlocked>> is a BSD extension also provided by GNU libc.
Supporting OS subroutines required: none.
*/
#include <_ansi.h>
#include <stdio.h>
#include <errno.h>
#include "local.h"
int
fileno (FILE * f)
{
int result;
CHECK_INIT (_REENT, f);
_newlib_flockfile_start (f);
if (f->_flags)
result = __sfileno (f);
else
{
result = -1;
_REENT_ERRNO(_REENT) = EBADF;
}
_newlib_flockfile_end (f);
return result;
}
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