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/* writev supports all Linux kernels >= 2.0.
Copyright (C) 1997-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library 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.
The GNU C 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stddef.h>
#include <sys/param.h>
#include <sys/uio.h>
#include <sysdep-cancel.h>
#include <sys/syscall.h>
#include <kernel-features.h>
#ifndef __ASSUME_COMPLETE_READV_WRITEV
static ssize_t __atomic_writev_replacement (int, const struct iovec *,
int) internal_function;
#endif
/* Not all versions of the kernel support the large number of records. */
#ifndef UIO_FASTIOV
# define UIO_FASTIOV 8 /* 8 is a safe number. */
#endif
ssize_t
__libc_writev (fd, vector, count)
int fd;
const struct iovec *vector;
int count;
{
ssize_t result;
if (SINGLE_THREAD_P)
result = INLINE_SYSCALL (writev, 3, fd, vector, count);
else
{
int oldtype = LIBC_CANCEL_ASYNC ();
result = INLINE_SYSCALL (writev, 3, fd, vector, count);
LIBC_CANCEL_RESET (oldtype);
}
#ifdef __ASSUME_COMPLETE_READV_WRITEV
return result;
#else
if (result >= 0 || errno != EINVAL || count <= UIO_FASTIOV)
return result;
return __atomic_writev_replacement (fd, vector, count);
#endif
}
strong_alias (__libc_writev, __writev)
weak_alias (__libc_writev, writev)
#ifndef __ASSUME_COMPLETE_READV_WRITEV
# define __libc_writev static internal_function __atomic_writev_replacement
# include <sysdeps/posix/writev.c>
#endif
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