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emacs/lib/fsync.c
Paul Eggert 6bbbc38b34 Merge from Gnulib
This incorporates:
2017-09-16 manywarnings: port to GCC on 64-bit MS-Windows
2017-09-13 all: Replace many more http URLs by https URLs
* build-aux/config.guess, build-aux/config.sub:
* build-aux/gitlog-to-changelog, doc/misc/texinfo.tex:
* lib/allocator.h, lib/count-leading-zeros.h:
* lib/count-trailing-zeros.h, lib/dup2.c, lib/filevercmp.c:
* lib/fstatat.c, lib/fsync.c, lib/ftoastr.c, lib/ftoastr.h:
* lib/intprops.h, lib/signal.in.h, lib/stdio-impl.h, lib/stdio.in.h:
* lib/unistd.in.h, lib/utimens.c, m4/alloca.m4, m4/extern-inline.m4:
* m4/fstatat.m4, m4/gnulib-common.m4, m4/manywarnings.m4:
* m4/std-gnu11.m4, m4/sys_types_h.m4, m4/vararrays.m4:
Copy from Gnulib.
* lib/gnulib.mk.in: Regenerate.
2017-09-17 13:06:54 -07:00

88 lines
2.3 KiB
C

/* 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) 2008-2017 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>
#if (defined _WIN32 || 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 */