diff --git a/extras/fixture/src/unity_fixture.c b/extras/fixture/src/unity_fixture.c
index 74269fb..b7afd68 100644
--- a/extras/fixture/src/unity_fixture.c
+++ b/extras/fixture/src/unity_fixture.c
@@ -28,7 +28,7 @@ void announceTestRun(unsigned int runNumber)
     UNITY_OUTPUT_CHAR('\n');
 }
 
-int UnityMain(int argc, char* argv[], void (*runAllTests)())
+int UnityMain(int argc, char* argv[], void (*runAllTests)(void))
 {
     int result = UnityGetCommandLineOptions(argc, argv);
     unsigned int r;