[libdv-dev] [PATCH] sched_setscheduler

[Michael W. <mfwitten@MIT.EDU>]

Hello,

Apparently sched_setscheduler() isn't quite fully supported,
and it certainly isn't defined in Mac OS X 10.5.3.

Following this:

	http://lists.apple.com/archives/Unix-porting/2005/Jul/msg00027.html

I have attached a patch that better handles the case in which
priority scheduling is not implemented (use the attached file,
because my MTA seems to remove empty lines, thereby corrupting
the patch; I should also note that I haven't really thought
about the consequences of my changes, though it should just
be rearrangement with a slight compile-time optimization due
to the use of preprocessor conditionals):

--- encodedv/dvconnect.c.old	2008-07-10 02:27:10.000000000 -0400
+++ encodedv/dvconnect.c	2008-07-10 02:26:38.000000000 -0400
@@ -857,24 +857,19 @@

  int rt_raisepri (int pri)
  {
-#ifdef _SC_PRIORITY_SCHEDULING
+#if (_POSIX_PRIORITY_SCHEDULING - 0) >=  200112L
  	struct sched_param scp;

-	/*
-	 * Verify that scheduling is available
-	 */
-	if (sysconf (_SC_PRIORITY_SCHEDULING) == -1) {
-		fprintf (stderr, "WARNING: RR-scheduler not available, "
-			 "disabling.\n");
-		return (-1);
-	} else {
-		memset (&scp, '\0', sizeof (scp));
-		scp.sched_priority = sched_get_priority_max (SCHED_RR) - pri;
-		if (sched_setscheduler (0, SCHED_RR, &scp) < 0)	{
-			fprintf (stderr, "WARNING: Cannot set RR-scheduler\n");
-			return (-1);
-		}
-	}
+    memset (&scp, '\0', sizeof (scp));
+    scp.sched_priority = sched_get_priority_max (SCHED_RR) - pri;
+    if (sched_setscheduler (0, SCHED_RR, &scp) < 0)	{
+        fprintf (stderr, "WARNING: Cannot set RR-scheduler, disabling 
\n");
+        return (-1);
+    }
+
+#else
+    fprintf (stderr, "WARNING: RR-scheduler not available, disabling. 
\n");
+    return (-1);
  #endif
  	return (0);
  }


Sincerely,
Michael Witten