diff --git a/nsprpub/pr/src/threads/prcthr.c b/nsprpub/pr/src/threads/prcthr.c
index 917884530193..5a4fa5024416 100644
--- a/nsprpub/pr/src/threads/prcthr.c
+++ b/nsprpub/pr/src/threads/prcthr.c
@@ -298,6 +298,8 @@ PR_IMPLEMENT(PRInt32) PR_SetThreadAffinityMask(PRThread *thread, PRUint32 mask )
 #ifdef HAVE_THREAD_AFFINITY
 #ifndef IRIX
     return _PR_MD_SETTHREADAFFINITYMASK(thread, mask);
+#else
+	return 0;
 #endif
 #else