glibc/stdio/fileno.c

51 lines
1.4 KiB
C

/* Copyright (C) 1991, 93, 94, 96, 97, 98 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include <stdio.h>
/* Return the system file descriptor associated with STREAM. */
int
fileno (stream)
FILE *stream;
{
extern void __stdio_check_funcs __P ((FILE *));
if (! __validfp (stream))
{
__set_errno (EINVAL);
return -1;
}
__stdio_check_funcs (stream);
if (stream->__io_funcs.__fileno == NULL)
{
#ifdef EOPNOTSUPP
__set_errno (EOPNOTSUPP);
#else
__set_errno (ENOSYS);
#endif
return -1;
}
return (*stream->__io_funcs.__fileno) (stream->__cookie);
}
weak_alias(fileno, fileno_unlocked)