/* Retrieve information about a FILE stream.
   Copyright (C) 2007 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include "fwritable.h"

bool
fwritable (FILE *fp)
{
  /* Most systems provide FILE as a struct and the necessary bitmask in
     <stdio.h>, because they need it for implementing getc() and putc() as
     fast macros.  */
#if defined _IO_ferror_unlocked     /* GNU libc, BeOS */
  return (fp->_flags & _IO_NO_WRITES) == 0;
#elif defined __sferror             /* FreeBSD, NetBSD, OpenBSD, MacOS X, Cygwin */
  return (fp->_flags & (__SRW | __SWR)) != 0;
#elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, mingw */
  return (fp->_flag & (_IORW | _IOWRT)) != 0;
#elif defined __QNX__               /* QNX */
  return (fp->_mode & _MOPENW) != 0;
#else
 #error "Please port gnulib fwritable.c to your platform! Look at the definition of fopen, fdopen on your system, then report this to bug-gnulib."
#endif
}