/* Set the error indicator of a 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 "fseterr.h"
#include <errno.h>
void
fseterr (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 */
fp->_flags |= _IO_ERR_SEEN;
#elif defined __sferror /* FreeBSD, NetBSD, OpenBSD, MacOS X, Cygwin */
fp->_flags |= __SERR;
#elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, mingw */
# if defined __sun && defined _LP64 /* Solaris/{SPARC,AMD64} 64-bit */
# define fp_ ((struct { unsigned char *_ptr; \
unsigned char *_base; \
unsigned char *_end; \
long _cnt; \
int _file; \
unsigned int _flag; \
} *) fp)
fp_->_flag |= _IOERR;
# else
fp->_flag |= _IOERR;
# endif
#elif defined __UCLIBC__ /* uClibc */
fp->__modeflags |= __FLAG_ERROR;
#elif defined __QNX__ /* QNX */
fp->_Mode |= 0x200 /* _MERR */;
#elif 0 /* unknown */
/* Portable fallback, based on an idea by Rich Felker.
Wow! 6 system calls for something that is just a bit operation!
Not activated on any system, because there is no way to repair FP when
the sequence of system calls fails, and library code should not call
abort(). */
int saved_errno;
int fd;
int fd2;
saved_errno = errno;
fflush (fp);
fd = fileno (fp);
fd2 = dup (fd);
if (fd2 >= 0)
{
close (fd);
fputc ('\0', fp); /* This should set the error indicator. */
fflush (fp); /* Or this. */
if (dup2 (fd2, fd) < 0)
/* Whee... we botched the stream and now cannot restore it! */
abort ();
close (fd2);
}
errno = saved_errno;
#else
#error "Please port gnulib fseterr.c to your platform! Look at the definitions of ferror and clearerr on your system, then report this to bug-gnulib."
#endif
}
