add warning

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

diff --git a/lib/safe-read.c b/lib/safe-read.c
index 7fd4415..eb0566b 100644 (file)
--- a/lib/safe-read.c
+++ b/lib/safe-read.c
@@ -1,5 +1,5 @@
 /* safe-read.c -- an interface to read that retries after interrupts
-   Copyright (C) 1993, 1994 Free Software Foundation, Inc.
+   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
@@ -12,54 +12,48 @@
    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.
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
    */
 
-#ifdef HAVE_CONFIG_H
-#include <config.h>
+#if HAVE_CONFIG_H
+# include <config.h>
 #endif
 
 #include <sys/types.h>
 
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
+#if HAVE_UNISTD_H
+# include <unistd.h>
 #endif
 
 #include <errno.h>
-#ifndef STDC_HEADERS
+#ifndef errno
 extern int errno;
 #endif
 
-/* Read LEN bytes at PTR from descriptor DESC, for file FILENAME,
-   retrying if necessary.  Return a negative value if an error occurs,
-   otherwise return the actual number of bytes read,
-   which must be LEN unless end-of-file was reached.  */
+#include "safe-read.h"
 
-   The canonical source for this function is in the gcc distribution
-   in file cccp.c.  So don't make any changes here.  */
+/* 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.  */
 
-static int
-safe_read (desc, ptr, len)
-     int desc;
-     char *ptr;
-     int len;
+ssize_t
+safe_read (int desc, char *ptr, size_t len)
 {
-  int left = len;
-  while (left > 0) {
-    int nchars = read (desc, ptr, left);
-    if (nchars < 0)
-      {
+  ssize_t n_chars;
+
+  if (len <= 0)
+    return len;
+
 #ifdef EINTR
-       if (errno == EINTR)
-         continue;
+  do
+    {
+      n_chars = read (desc, ptr, len);
+    }
+  while (n_chars < 0 && errno == EINTR);
+#else
+  n_chars = read (desc, ptr, len);
 #endif
-       return nchars;
-      }
-    if (nchars == 0)
-      break;
-    ptr += nchars;
-    left -= nchars;
-  }
-  return len - left;
+
+  return n_chars;
 }