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Date :
2025-01-01T09:24:36
maint: run 'make update-copyright'
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/* Write block to given position in file without changing file pointer.
POSIX version.
Copyright (C) 1997-1999, 2002, 2011-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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.
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 <unistd.h>
#include <errno.h>
#define __libc_lseek(f,o,w) lseek (f, o, w)
#define __set_errno(Val) errno = (Val)
#define __libc_write(f,b,n) write (f, b, n)
/* Note: This implementation of pwrite is not multithread-safe. */
ssize_t
pwrite (int fd, const void *buf, size_t nbyte, off_t offset)
{
/* Since we must not change the file pointer preserve the value so that
we can restore it later. */
int saved_errno;
ssize_t result;
off_t old_offset = __libc_lseek (fd, 0, SEEK_CUR);
if (old_offset == (off_t) -1)
return -1;
/* Set to wanted position. */
if (__libc_lseek (fd, offset, SEEK_SET) == (off_t) -1)
return -1;
/* Write out the data. */
result = __libc_write (fd, buf, nbyte);
/* Now we have to restore the position. If this fails we have to
return this as an error. But if the writing also failed we
return this error. */
saved_errno = errno;
if (__libc_lseek (fd, old_offset, SEEK_SET) == (off_t) -1)
{
if (result == -1)
__set_errno (saved_errno);
return -1;
}
__set_errno (saved_errno);
return result;
}