nice/setpriority fixes

[Bruce <bruce at puremagic dot com>]

The attached patch fixes the bug reported on bug-glibc.

  - Bruce

2001-06-04  Bruce Mitchener  <bruce@cubik.org>

         * manual/resource.texi: Correct setpriority/nice
         documentation.

         * sysdeps/unix/nice.c: Correct nice() implementation.
Index: manual/resource.texi
===================================================================
RCS file: /cvs/glibc/libc/manual/resource.texi,v
retrieving revision 1.10
diff -u -r1.10 resource.texi
--- resource.texi	2001/05/21 16:19:34	1.10
+++ resource.texi	2001/06/04 18:04:24
@@ -1170,7 +1170,7 @@
 Set the nice value of a set of processes to @var{niceval}; @var{class}
 and @var{id} specify which ones (see below).
 
-The return value is the nice value on success, and @code{-1} on
+The return value is @code{0} on success, and @code{-1} on
 failure.  The following @code{errno} error condition are possible for
 this function:
 
@@ -1225,7 +1225,9 @@
 @comment BSD
 @deftypefun int nice (int @var{increment})
 Increment the nice value of the calling process by @var{increment}.
-The return value is the same as for @code{setpriority}.
+The return value is the new nice value on success, and @code{-1} on
+failure.  In the case of failuer, @code{errno} will be set to the
+same values as for @code{setpriority}. .
 
 Here is an equivalent definition of @code{nice}:
 
@@ -1233,8 +1235,12 @@
 int
 nice (int increment)
 @{
-  int old = getpriority (PRIO_PROCESS, 0);
-  return setpriority (PRIO_PROCESS, 0, old + increment);
+  int result, old = getpriority (PRIO_PROCESS, 0);
+  result = setpriority (PRIO_PROCESS, 0, old + increment);
+  if (result != -1)
+      return old - increment;
+  else
+      return -1;
 @}
 @end smallexample
 @end deftypefun
Index: sysdeps/unix/nice.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/unix/nice.c,v
retrieving revision 1.3
diff -u -r1.3 nice.c
--- nice.c	1997/06/23 21:53:50	1.3
+++ nice.c	2001/06/04 18:04:34
@@ -28,6 +28,7 @@
 {
   int save;
   int prio;
+  int result;
 
   /* -1 is a valid priority, so we use errno to check for an error.  */
   save = errno;
@@ -41,5 +42,9 @@
 	__set_errno (save);
     }
 
-  return setpriority (PRIO_PROCESS, 0, prio + incr);
+  result = setpriority (PRIO_PROCESS, 0, prio + incr);
+  if (result != -1)
+    return prio + incr;
+  else
+    return -1;
 }