/* full-write.c -- an interface to write that retries after interrupts
   Copyright (C) 1993, 1994 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
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program 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 General Public License for more details.

   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., 675 Mass Ave, Cambridge, MA 02139, USA.

   Copied largely from GNU C's cccp.c.
   */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <sys/types.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <errno.h>
#ifndef errno
extern int errno;
#endif

/* Write LEN bytes at PTR to descriptor DESC, retrying if interrupted.
   Return LEN upon success, write's (negative) error code otherwise.
   As the name implies, this function writes all LEN bytes and returns
   LEN or it fails and returns the negative value returned by the (final)
   failing write.  */

int
full_write (desc, ptr, len)
     int desc;
     char *ptr;
     size_t len;
{
  int total_written;

  total_written = 0;
  while (len > 0)
    {
      int written = write (desc, ptr, len);
      if (written < 0)
	{
#ifdef EINTR
	  if (errno == EINTR)
	    continue;
#endif
	  return written;
	}
      total_written += written;
      ptr += written;
      len -= written;
    }
  return total_written;
}