--- APC-3.1.9/apc_sem.c_orig	Sat May 14 15:14:56 2011
+++ APC-3.1.9/apc_sem.c	Tue Dec 13 16:01:59 2011
@@ -76,12 +76,16 @@
     union semun arg;
     key_t key = IPC_PRIVATE;
 
-    if ((semid = semget(key, 1, IPC_CREAT | IPC_EXCL | perms)) >= 0) {
+    if ((semid = semget(key, 2, IPC_CREAT | IPC_EXCL | perms)) >= 0) {
         /* sempahore created for the first time, initialize now */
         arg.val = initval;
         if (semctl(semid, 0, SETVAL, arg) < 0) {
             apc_error("apc_sem_create: semctl(%d,...) failed:" TSRMLS_CC, semid);
         }
+	arg.val = getpid();
+	if (semctl(semid, 1, SETVAL, arg) < 0) {
+	    apc_error("apc_sem_create: semctl(%d,...) failed:", TSRMLS_CC, semid);
+	}
     }
     else if (errno == EEXIST) {
         /* sempahore already exists, don't initialize */
@@ -101,7 +105,10 @@
 {
     /* we expect this call to fail often, so we do not check */
     union semun arg;
-    semctl(semid, 0, IPC_RMID, arg);
+    int semPid = semctl(semid, 1, GETVAL, 0);
+    if (semPid == getpid()) {
+        semctl(semid, 0, IPC_RMID, arg);
+    }
 }
 
 void apc_sem_lock(int semid TSRMLS_DC)