/* safe-read.c -- an interface to read that retries after interrupts   Copyright (C) 1993, 1994, 1998 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.   */#if HAVE_CONFIG_H# include <config.h>#endif#include <sys/types.h>#if HAVE_UNISTD_H# include <unistd.h>#endif#include <errno.h>#ifndef errnoextern int errno;#endif#include "safe-read.h"/* Read LEN bytes at PTR from descriptor DESC, retrying if interrupted.   Return the actual number of bytes read, zero for EOF, or negative   for an error.  */ssize_tsafe_read (int desc, void *ptr, size_t len){  ssize_t n_chars;  if (len <= 0)    return len;#ifdef EINTR  do    {      n_chars = read (desc, ptr, len);    }  while (n_chars < 0 && errno == EINTR);#else  n_chars = read (desc, ptr, len);#endif  return n_chars;}