1 /* Copyright (C) 2009 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
25 #include <sys/param.h>
26 #if __WORDSIZE == 64 && !defined PWRITEV
27 /* Hide the pwritev64 declaration. */
28 # define pwritev64 __redirect_pwritev64
31 #include <bits/wordsize.h>
34 # define PWRITEV pwritev
35 # define PWRITE __pwrite
47 /* Write data pointed by the buffers described by IOVEC, which is a
48 vector of COUNT 'struct iovec's, to file descriptor FD at the given
49 position OFFSET without change the file pointer. The data is
50 written in the order specified. Operates just like 'write' (see
51 <unistd.h>) except that the data are taken from IOVEC instead of a
54 PWRITEV (int fd
, const struct iovec
*vector
, int count
, OFF_T offset
)
56 /* Find the total number of bytes to be read. */
58 for (int i
= 0; i
< count
; ++i
)
60 /* Check for ssize_t overflow. */
61 if (SSIZE_MAX
- bytes
< vector
[i
].iov_len
)
66 bytes
+= vector
[i
].iov_len
;
69 /* Allocate a temporary buffer to hold the data. We should normally
70 use alloca since it's faster and does not require synchronization
71 with other threads. But we cannot if the amount of memory
72 required is too large. */
74 char *malloced_buffer
__attribute__ ((__cleanup__ (ifree
))) = NULL
;
75 if (__libc_use_alloca (bytes
))
76 buffer
= (char *) __alloca (bytes
);
79 malloced_buffer
= buffer
= (char *) malloc (bytes
);
84 /* Copy the data from BUFFER into the memory specified by VECTOR. */
86 for (int i
= 0; i
< count
; ++i
)
87 ptr
= __mempcpy ((void *) ptr
, (void *) vector
[i
].iov_base
,
91 return PWRITE (fd
, buffer
, bytes
, offset
);
93 #if __WORDSIZE == 64 && defined pwritev64
95 strong_alias (pwritev
, pwritev64
)