diff --git a/samples/microkernel/test/test_sema/src/sema.c b/samples/microkernel/test/test_sema/src/sema.c
index d7bca22be24..508bfe6314e 100644
--- a/samples/microkernel/test/test_sema/src/sema.c
+++ b/samples/microkernel/test/test_sema/src/sema.c
@@ -50,7 +50,7 @@ This modules tests the following semaphore routines:
 
 #include <util_test_common.h>
 
-extern void trigger_isrSemaSignal();
+extern void trigger_isrSemaSignal(ksem_t semaphore);
 extern void releaseTestFiber (void);
 
 /* defines */