aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/posix/writev.c
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/posix/writev.c')
-rw-r--r--sysdeps/posix/writev.c64
1 files changed, 64 insertions, 0 deletions
diff --git a/sysdeps/posix/writev.c b/sysdeps/posix/writev.c
new file mode 100644
index 0000000000..56e29a64b9
--- /dev/null
+++ b/sysdeps/posix/writev.c
@@ -0,0 +1,64 @@
+/* Copyright (C) 1991, 1992 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 Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA. */
+
+#include <ansidecl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/uio.h>
+
+/* Write data pointed by the buffers described by VECTOR, which
+ is a vector of COUNT `struct iovec's, to file descriptor FD.
+ The data is written in the order specified.
+ Operates just like `write' (see <unistd.h>) except that the data
+ are taken from VECTOR instead of a contiguous buffer. */
+int
+DEFUN(writev, (fd, vector, count),
+ int fd AND CONST struct iovec *vector AND size_t count)
+{
+ char *buffer;
+ register char *bp;
+ size_t bytes, to_copy;
+ register size_t i;
+
+ /* Find the total number of bytes to be written. */
+ bytes = 0;
+ for (i = 0; i < count; ++i)
+ bytes += vector[i].iov_len;
+
+ /* Allocate a temporary buffer to hold the data. */
+ buffer = (char *) __alloca(bytes);
+
+ /* Copy the data into BUFFER. */
+ to_copy = bytes;
+ bp = buffer;
+ for (i = 0; i < count; ++i)
+ {
+#define min(a, b) ((a) > (b) ? (b) : (a))
+ size_t copy = min(vector[i].iov_len, to_copy);
+
+ (void) memcpy((PTR) bp, (PTR) vector[i].iov_base, copy);
+
+ bp += copy;
+ to_copy -= copy;
+ if (bytes == 0)
+ break;
+ }
+
+ return write(fd, buffer, bytes);
+}