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e61abf83 UD |
1 | /* writev supports all Linux kernels >= 2.0. |
2 | Copyright (C) 1997 Free Software Foundation, Inc. | |
3 | This file is part of the GNU C Library. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Library General Public License as | |
7 | published by the Free Software Foundation; either version 2 of the | |
8 | License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Library General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Library General Public | |
16 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
17 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
18 | Boston, MA 02111-1307, USA. */ | |
19 | ||
20 | #include <errno.h> | |
21 | #include <stddef.h> | |
22 | #include <sys/param.h> | |
23 | #include <sys/uio.h> | |
24 | ||
25 | extern ssize_t __syscall_writev __P ((int, const struct iovec *, int)); | |
5ae9d168 UD |
26 | static ssize_t __atomic_writev_replacement __P ((int, const struct iovec *, |
27 | int)); | |
28 | ||
e61abf83 UD |
29 | |
30 | /* Not all versions of the kernel support the large number of records. */ | |
c57abfa7 UD |
31 | #ifndef UIO_FASTIOV |
32 | # define UIO_FASTIOV 8 /* 8 is a safe number. */ | |
e61abf83 UD |
33 | #endif |
34 | ||
35 | ||
c57abfa7 | 36 | /* We should deal with kernel which have a smaller UIO_FASTIOV as well |
e61abf83 UD |
37 | as a very big count. */ |
38 | ssize_t | |
5ae9d168 | 39 | __writev (fd, vector, count) |
e61abf83 UD |
40 | int fd; |
41 | const struct iovec *vector; | |
42 | int count; | |
43 | { | |
44 | int errno_saved = errno; | |
45 | ssize_t bytes_written; | |
46 | ||
47 | bytes_written = __syscall_writev (fd, vector, count); | |
48 | ||
5ae9d168 UD |
49 | if (bytes_written >= 0 || errno != EINVAL || count <= UIO_FASTIOV) |
50 | return bytes_written; | |
e61abf83 | 51 | |
5ae9d168 UD |
52 | /* Restore the old error value as if nothing happened. */ |
53 | __set_errno (errno_saved); | |
e61abf83 | 54 | |
5ae9d168 | 55 | return __atomic_writev_replacement (fd, vector, count); |
e61abf83 | 56 | } |
5ae9d168 UD |
57 | weak_alias (__writev, writev) |
58 | ||
59 | #define __writev static __atomic_writev_replacement | |
60 | #include <sysdeps/posix/writev.c> |