rm_/lib/fseterr.c

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/* Set the error indicator of a stream.
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Copyright (C) 2007-2022 Free Software Foundation, Inc.
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This file 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.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "fseterr.h"
#include <errno.h>
#include "stdio-impl.h"
/* This file is not used on systems that have the __fseterr function,
namely musl libc. */
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_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
/* GNU libc, BeOS, Haiku, Linux libc5 */
fp->_flags |= _IO_ERR_SEEN;
#elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
/* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
fp_->_flags |= __SERR;
#elif defined __EMX__ /* emx+gcc */
fp->_flags |= _IOERR;
#elif defined __minix /* Minix */
fp->_flags |= _IOERR;
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#elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
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fp_->_flag |= _IOERR;
#elif defined __UCLIBC__ /* uClibc */
fp->__modeflags |= __FLAG_ERROR;
#elif defined __QNX__ /* QNX */
fp->_Mode |= 0x200 /* _MERR */;
#elif defined __MINT__ /* Atari FreeMiNT */
fp->__error = 1;
#elif defined EPLAN9 /* Plan9 */
if (fp->state != 0 /* CLOSED */)
fp->state = 5 /* ERR */;
#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
}