Index: /trunk/source/lisp-kernel/thread_manager.c
===================================================================
--- /trunk/source/lisp-kernel/thread_manager.c	(revision 15332)
+++ /trunk/source/lisp-kernel/thread_manager.c	(revision 15333)
@@ -682,6 +682,10 @@
 #endif
 #ifdef USE_MACH_SEMAPHORES
+  kern_return_t kret;
   semaphore_t s = (semaphore_t)0;
-  semaphore_create(mach_task_self(),&s, SYNC_POLICY_FIFO, count);
+  kret = semaphore_create(mach_task_self(),&s, SYNC_POLICY_FIFO, count);
+  if (kret != KERN_SUCCESS) {
+    fatal_oserr("Can't create Mach semaphore.",(OSErr)kret);
+  }
   return (void *)(natural)s;
 #endif