X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/mLib/blobdiff_plain/8656dc507aee9c5dcb3a6ad876565f5fcac425ae..9fcce036ef8b14c12fc4482efc7c8cf75da3b31f:/fdflags.c

diff --git a/fdflags.c b/fdflags.c
index ae9cf6a..af8663f 100644
--- a/fdflags.c
+++ b/fdflags.c
@@ -1,13 +1,13 @@
 /* -*-c-*-
  *
- * $Id: fdflags.c,v 1.2 2004/04/08 01:36:11 mdw Exp $
+ * $Id$
  *
  * Manipulates flags on file descriptors
  *
  * (c) 1999 Straylight/Edgeware
  */
 
-/*----- Licensing notice --------------------------------------------------* 
+/*----- Licensing notice --------------------------------------------------*
  *
  * This file is part of the mLib utilities library.
  *
@@ -15,12 +15,12 @@
  * it under the terms of the GNU Library General Public License as
  * published by the Free Software Foundation; either version 2 of the
  * License, or (at your option) any later version.
- * 
+ *
  * mLib 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 Library General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Library General Public
  * License along with mLib; if not, write to the Free
  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
@@ -54,13 +54,22 @@
 int fdflags(int fd, unsigned fbic, unsigned fxor,
 	    unsigned fdbic, unsigned fdxor)
 {
-  int f;
+  int f, ff;
 
-  if ((f = fcntl(fd, F_GETFL)) == -1 ||
-      fcntl(fd, F_SETFL, (f & ~fbic) ^ fxor) == -1 ||
-      (f = fcntl(fd, F_GETFD)) == -1 ||
-      fcntl(fd, F_SETFD, (f & ~fdbic) ^ fdxor) == -1)
-    return (-1);
+  if (fbic || fxor) {
+    if ((f = fcntl(fd, F_GETFL)) == -1)
+      return (-1);
+    ff = (f & ~fbic) ^ fxor;
+    if (f != ff && fcntl(fd, F_SETFL, ff) == -1)
+      return (-1);
+  }
+  if (fdbic || fdxor) {
+    if ((f = fcntl(fd, F_GETFD)) == -1)
+      return (-1);
+    ff = (f & ~fdbic) ^ fdxor;
+    if (f != ff && fcntl(fd, F_SETFD, ff) == -1)
+      return (-1);
+  }
   return (0);
 }