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import from gnulib

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This commit is contained in:
Paul Eggert
2003-01-08 18:42:38 +00:00
parent 4f5e37c861
commit 7154feb583
1 changed files with 54 additions and 36 deletions
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90
lib/full-write.c
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@@ -1,7 +1,6 @@
/* full-write.c -- an interface to write that retries after interrupts
/* An interface to read and write that retries (if necessary) until complete.
Copyright 1993, 1994, 1997, 1998, 1999, 2000, 2001 Free Software
Foundation, Inc.
Copyright (C) 1993, 1994, 1997-2003 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@@ -15,20 +14,17 @@
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
Written by Paul Eggert. */
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <sys/types.h>
#include "full-write.h"
#if HAVE_UNISTD_H
# include <unistd.h>
/* Specification. */
#ifdef FULL_READ
# include "full-read.h"
#else
# include "full-write.h"
#endif
#include <errno.h>
@@ -36,32 +32,54 @@
extern int errno;
#endif
/* Write LEN bytes at PTR to descriptor DESC, retrying if interrupted
or if partial writes occur. Return the number of bytes successfully
written, setting errno if that is less than LEN. */
size_t
full_write (int desc, const char *ptr, size_t len)
{
size_t total_written = 0;
while (len > 0)
{
ssize_t written = write (desc, ptr, len);
if (written <= 0)
{
/* Some buggy drivers return 0 when you fall off a device's end. */
if (written == 0)
errno = ENOSPC;
#ifdef EINTR
if (errno == EINTR)
continue;
#ifdef FULL_READ
# include "safe-read.h"
# define safe_rw safe_read
# define full_rw full_read
# undef const
# define const /* empty */
#else
# include "safe-write.h"
# define safe_rw safe_write
# define full_rw full_write
#endif
#ifdef FULL_READ
/* Set errno to zero upon EOF. */
# define ZERO_BYTE_TRANSFER_ERRNO 0
#else
/* Some buggy drivers return 0 when one tries to write beyond
a device's end. (Example: Linux 1.2.13 on /dev/fd0.)
Set errno to ENOSPC so they get a sensible diagnostic. */
# define ZERO_BYTE_TRANSFER_ERRNO ENOSPC
#endif
/* Write(read) COUNT bytes at BUF to(from) descriptor FD, retrying if
interrupted or if a partial write(read) occurs. Return the number
of bytes transferred.
When writing, set errno if fewer than COUNT bytes are written.
When reading, if fewer than COUNT bytes are read, you must examine
errno to distinguish failure from EOF (errno == 0). */
size_t
full_rw (int fd, const void *buf, size_t count)
{
size_t total = 0;
const char *ptr = buf;
while (count > 0)
{
size_t n_rw = safe_rw (fd, ptr, count);
if (n_rw == (size_t) -1)
break;
if (n_rw == 0)
{
errno = ZERO_BYTE_TRANSFER_ERRNO;
break;
}
total_written += written;
ptr += written;
len -= written;
total += n_rw;
ptr += n_rw;
count -= n_rw;
}
return total_written;
return total;
}