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emacs/lib/fsync.c

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/* Emulate fsync on platforms that lack it, primarily Windows and
cross-compilers like MinGW.
This is derived from sqlite3 sources.
https://www.sqlite.org/src/finfo?name=src/os_win.c
https://www.sqlite.org/copyright.html
Written by Richard W.M. Jones <rjones.at.redhat.com>
Copyright (C) 2008-2019 Free Software Foundation, Inc.
This library 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 library 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 <https://www.gnu.org/licenses/>. */
#include <config.h>
#include <unistd.h>
Update from Gnulib This incorporates: 2018-05-21 crypto: omit stream ops Emacs doesn’t need 2018-05-13 truncate: Fix compilation error on Android 2018-05-13 imaxdiv: Fix compilation error on Android 2018-05-13 Support selective inclusion of recent mingw.org headers 2018-05-13 Add cross-compilation guesses for Linux systems sans glibc 2018-05-13 stdioext: Fix compilation errors with newer Android headers 2018-05-07 af_alg: Pacify --enable-gcc-warnings 2018-05-06 af_alg: Fix bug with streams that are not at position 0 2018-05-06 Followup to 'af_alg: New module' 2018-05-05 crypto/{md5,sha1,sha256,sha512}: simplify 2018-05-05 af_alg: New module 2018-05-05 af_alg: Improve function signature 2018-04-28 md5sum: Use AF_ALG when available 2018-04-28 sha512sum: Use AF_ALG when available 2018-04-28 sha256sum: Use AF_ALG when available 2018-04-28 sha1sum: Use AF_ALG when available 2018-05-05 all: Replace more http URLs by https URLs 2018-05-03 maint: port more modules to GCC 8 2018-05-03 Simplify code; drop support for Borland C++ on Windows * admin/merge-gnulib (GNULIB_MODULES): Use crypto/md5-buffer rather than crypto/md5, since Emacs doesn’t use the stream operations that in recent Gnulib pull in other stuff Emacs doesn’t need. Similarly for crypto/sha1-buffer, crypto/sha256-buffer, crypto/sha512-buffer. * build-aux/config.guess, build-aux/config.sub, lib/dosname.h: * lib/dup2.c, lib/errno.in.h, lib/euidaccess.c, lib/fcntl.c: * lib/fcntl.in.h, lib/fpending.c, lib/fsync.c, lib/getdtablesize.c: * lib/getopt.c, lib/gettimeofday.c, lib/inttypes.in.h, lib/md5.c: * lib/md5.h, lib/open.c, lib/pipe2.c, lib/putenv.c, lib/sha1.c: * lib/sha1.h, lib/sha256.c, lib/sha256.h, lib/sha512.c: * lib/sha512.h, lib/stat-time.h, lib/stdio-impl.h, lib/stdio.in.h: * lib/stdlib.in.h, lib/sys_stat.in.h, lib/sys_types.in.h: * lib/timespec.h, lib/unistd.in.h, lib/utimens.c, m4/c-strtod.m4: * m4/gnulib-common.m4, m4/inttypes.m4, m4/lstat.m4, m4/nocrash.m4: * m4/pselect.m4, m4/readlink.m4, m4/stdio_h.m4, m4/symlink.m4: * m4/unistd_h.m4, m4/utimens.m4: Copy from Gnulib. * lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
2018-05-21 18:42:18 +00:00
#if defined _WIN32 && ! defined __CYGWIN__
/* FlushFileBuffers */
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
# include <errno.h>
/* Get _get_osfhandle. */
# if GNULIB_MSVC_NOTHROW
# include "msvc-nothrow.h"
# else
# include <io.h>
# endif
int
fsync (int fd)
{
HANDLE h = (HANDLE) _get_osfhandle (fd);
DWORD err;
if (h == INVALID_HANDLE_VALUE)
{
errno = EBADF;
return -1;
}
if (!FlushFileBuffers (h))
{
/* Translate some Windows errors into rough approximations of Unix
* errors. MSDN is useless as usual - in this case it doesn't
* document the full range of errors.
*/
err = GetLastError ();
switch (err)
{
case ERROR_ACCESS_DENIED:
/* For a read-only handle, fsync should succeed, even though we have
no way to sync the access-time changes. */
return 0;
/* eg. Trying to fsync a tty. */
case ERROR_INVALID_HANDLE:
errno = EINVAL;
break;
default:
errno = EIO;
}
return -1;
}
return 0;
}
#else /* !Windows */
# error "This platform lacks fsync function, and Gnulib doesn't provide a replacement. This is a bug in Gnulib."
#endif /* !Windows */