.

[gnulib.git] / lib / safe-read.c

diff --git a/lib/safe-read.c b/lib/safe-read.c
index d915d4e..93d35e4 100644 (file)
--- a/lib/safe-read.c
+++ b/lib/safe-read.c
@@ -1,4 +1,37 @@
-/* Read LEN bytes at PTR from descriptor DESC, retrying if necessary.
+/* safe-read.c -- an interface to read 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.
+   */
+
+#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
+
+/* 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.  */
 
@@ -8,24 +41,20 @@ safe_read (desc, ptr, len)
      char *ptr;
      int len;
 {
-  int n_remaining;
+  int n_chars;
+
+  if (len <= 0)
+    return len;
 
-  n_remaining = len;
-  while (n_remaining > 0)
-    {
-      int n_chars = read (desc, ptr, n_remaining);
-      if (n_chars < 0)
-       {
 #ifdef EINTR
-         if (errno == EINTR)
-           continue;
-#endif
-         return n_chars;
-       }
-      if (n_chars == 0)
-       break;
-      ptr += n_chars;
-      n_remaining -= n_chars;
+  do
+    {
+      n_chars = read (desc, ptr, len);
     }
-  return len - n_remaining;
+  while (n_chars < 0 && errno == EINTR);
+#else
+  n_chars = read (desc, ptr, len);
+#endif
+
+  return n_chars;
 }