diff --git a/linuxthreads/semaphore.h b/linuxthreads/semaphore.h
index 1d5f933da3..84742233b6 100644
--- a/linuxthreads/semaphore.h
+++ b/linuxthreads/semaphore.h
@@ -39,7 +39,7 @@ typedef struct
 
 
 /* Value returned if `sem_open' failed.  */
-#define SEM_FAILED	((sem_t *) NULL)
+#define SEM_FAILED	((sem_t *) 0)
 
 /* Maximum value the semaphore can have.  */
 #define SEM_VALUE_MAX 	((int) ((~0u) >> 1))