diff --git a/newlib/libc/sys/rtems/include/sys/lock.h b/newlib/libc/sys/rtems/include/sys/lock.h
index 85b0cd8c4..d6169025b 100644
--- a/newlib/libc/sys/rtems/include/sys/lock.h
+++ b/newlib/libc/sys/rtems/include/sys/lock.h
@@ -300,8 +300,12 @@ int _Semaphore_Wait_timed(struct _Semaphore_Control *,
 
 int _Semaphore_Wait_timed_ticks(struct _Semaphore_Control *, __uint32_t);
 
+int _Semaphore_Try_wait(struct _Semaphore_Control *);
+
 void _Semaphore_Post(struct _Semaphore_Control *);
 
+void _Semaphore_Post_binary(struct _Semaphore_Control *);
+
 static __inline void
 _Semaphore_Destroy(struct _Semaphore_Control *_semaphore)
 {