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Collin Funk
70 lines
2.6 KiB
C
70 lines
2.6 KiB
C
/* Retrieve information about a FILE stream.
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Copyright (C) 2007-2026 Free Software Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation, either version 3 of the
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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
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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/>. */
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#include <config.h>
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/* Specification. */
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#include "fwritable.h"
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#include "stdio-impl.h"
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#if defined EPLAN9 /* Plan9 */
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# include <fcntl.h>
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#endif
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/* This file is not used on systems that have the __fwritable function,
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namely glibc >= 2.2, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.34,
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Android API >= 23, musl libc, Haiku >= hrev58760. */
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bool
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fwritable (FILE *fp)
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{
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/* Most systems provide FILE as a struct and the necessary bitmask in
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<stdio.h>, because they need it for implementing getc() and putc() as
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fast macros. */
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#if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
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/* GNU libc, BeOS, Haiku, Linux libc5 */
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return (fp->_flags & _IO_NO_WRITES) == 0;
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#elif defined __sferror || defined __OpenBSD__ || defined __DragonFly__ || defined __ANDROID__
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/* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin < 1.7.34, Minix 3, Android */
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return (fp_->_flags & (__SRW | __SWR)) != 0;
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#elif defined __EMX__ /* emx+gcc */
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return (fp->_flags & (_IORW | _IOWRT)) != 0;
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#elif defined __minix /* Minix */
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return (fp->_flags & _IOWRITE) != 0;
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#elif defined _IOERR /* AIX, HP-UX, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
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return (fp_->_flag & (_IORW | _IOWRT)) != 0;
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#elif defined __QNX__ /* QNX */
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return (fp->_Mode & 0x2 /* _MOPENW */) != 0;
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#elif defined __MINT__ /* Atari FreeMiNT */
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return fp->__mode.__write;
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#elif defined EPLAN9 /* Plan9 */
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int fd = fp->fd;
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if (fd >= 0)
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{
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int flags = fcntl (fd, F_GETFL, NULL);
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if (flags >= 0)
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{
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flags &= O_ACCMODE;
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return (flags == O_WRONLY || flags == O_RDWR);
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}
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}
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return 0;
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#else
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# 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."
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#endif
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}
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