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/* Retrieve information about a FILE stream.
Copyright (C) 2007-2021 Free Software Foundation, Inc.
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 3 of the
License, or (at your option) any later version.
This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "fwritable.h"
#include "stdio-impl.h"
#if defined EPLAN9 /* Plan9 */
# include <fcntl.h>
#endif
/* This file is not used on systems that have the __fwritable function,
namely glibc >= 2.2, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.34,
Android API >= 23, musl libc. */
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_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
/* GNU libc, BeOS, Haiku, Linux libc5 */
return (fp->_flags & _IO_NO_WRITES) == 0;
#elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
/* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin < 1.7.34, Minix 3, Android */
return (fp_->_flags & (__SRW | __SWR)) != 0;
#elif defined __EMX__ /* emx+gcc */
return (fp->_flags & (_IORW | _IOWRT)) != 0;
#elif defined __minix /* Minix */
return (fp->_flags & _IOWRITE) != 0;
#elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
return (fp_->_flag & (_IORW | _IOWRT)) != 0;
#elif defined __QNX__ /* QNX */
return (fp->_Mode & 0x2 /* _MOPENW */) != 0;
#elif defined __MINT__ /* Atari FreeMiNT */
return fp->__mode.__write;
#elif defined EPLAN9 /* Plan9 */
int fd = fp->fd;
if (fd >= 0)
{
int flags = fcntl (fd, F_GETFL, NULL);
if (flags >= 0)
{
flags &= O_ACCMODE;
return (flags == O_WRONLY || flags == O_RDWR);
}
}
return 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
}
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