diff --git a/Documentation/NuttxUserGuide.html b/Documentation/NuttxUserGuide.html
index 0a8233775c..47cb387d30 100644
--- a/Documentation/NuttxUserGuide.html
+++ b/Documentation/NuttxUserGuide.html
@@ -3697,7 +3697,7 @@ semaphores must be less than or equal to <code>SEM_VALUE_MAX</code> (defined in
 <p>
 <b>Returned Value:</b>
 <ul>
-<li>A pointer to sem_t or -1 (<code>ERROR</code>) if unsuccessful.
+<li>A pointer to sem_t or <code>SEM_FAILED</code> if unsuccessful.
 </ul>
 
 <p>
diff --git a/drivers/wireless/cc3000/cc3000drv.c b/drivers/wireless/cc3000/cc3000drv.c
index ab114c0515..6327371a47 100644
--- a/drivers/wireless/cc3000/cc3000drv.c
+++ b/drivers/wireless/cc3000/cc3000drv.c
@@ -192,7 +192,7 @@ static void *unsoliced_thread_func(void *parameter)
   DEBUGASSERT(SEM_NAMELEN == QUEUE_NAMELEN);
   snprintf(buff, SEM_NAMELEN, SEM_FORMAT, minor);
   spiconf.done = sem_open(buff, O_RDONLY);
-  DEBUGASSERT(spiconf.done != (sem_t *)-1);
+  DEBUGASSERT(spiconf.done != SEM_FAILED);
 
   sem_post(&spiconf.unsoliced_thread_wakesem);
 
diff --git a/fs/semaphore/sem_open.c b/fs/semaphore/sem_open.c
index aad94091b1..4055b66ba7 100644
--- a/fs/semaphore/sem_open.c
+++ b/fs/semaphore/sem_open.c
@@ -94,7 +94,7 @@
  *        SEM_VALUE_MAX.
  *
  * Return Value:
- *   A pointer to sem_t or -1 (ERROR) if unsuccessful.
+ *   A pointer to sem_t or SEM_FAILED if unsuccessful.
  *
  * Assumptions:
  *
@@ -257,7 +257,7 @@ errout_with_lock:
   RELEASE_SEARCH(&desc);
   set_errno(errcode);
   sched_unlock();
-  return (FAR sem_t *)ERROR;
+  return SEM_FAILED;
 }
 
 #endif /* CONFIG_FS_NAMED_SEMAPHORES */
diff --git a/include/semaphore.h b/include/semaphore.h
index e14b1aa409..9a87461edf 100644
--- a/include/semaphore.h
+++ b/include/semaphore.h
@@ -49,6 +49,10 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Value returned by sem_open() in the event of a failure. */
+
+#define SEM_FAILED ((FAR sem_t *)NULL)
+
 /* Bit definitions for the struct sem_s flags field */
 
 #define PRIOINHERIT_FLAGS_DISABLE (1 << 0)  /* Bit 0: Priority inheritance