diff --git a/DebugUtils/GTMMethodCheck.h b/DebugUtils/GTMMethodCheck.h
index 644e8fe..a307929 100644
--- a/DebugUtils/GTMMethodCheck.h
+++ b/DebugUtils/GTMMethodCheck.h
@@ -52,7 +52,7 @@ NS_ASSUME_NONNULL_BEGIN
 //    implementation for |method| (either a class method or an instance method).
 #define GTM_METHOD_CHECK_INNER_INNER(class, method, line) \
 __attribute__ ((constructor, visibility("hidden"))) \
-    static void xxGTMMethodCheckMethod ## class ## line () { \
+    static void xxGTMMethodCheckMethod ## class ## line (void) { \
   @autoreleasepool { \
     if (![class instancesRespondToSelector:@selector(method)] \
         && ![class respondsToSelector:@selector(method)]) { \
diff --git a/Foundation/GTMTimeUtils.m b/Foundation/GTMTimeUtils.m
index 2b551e4..ed68779 100644
--- a/Foundation/GTMTimeUtils.m
+++ b/Foundation/GTMTimeUtils.m
@@ -59,13 +59,13 @@ struct timeval GTMAppLaunchTimeRelativeTo1970(void) {
   return info.kp_proc.p_starttime;
 }
 
-NSDate *GTMAppLaunchDate() {
+NSDate *GTMAppLaunchDate(void) {
   NSTimeInterval ti =
       GTMTimeValToNSTimeInterval(GTMAppLaunchTimeRelativeTo1970());
   return [NSDate dateWithTimeIntervalSince1970:ti];
 }
 
-NSDate *GTMBootDate() {
+NSDate *GTMBootDate(void) {
   NSTimeInterval ti =
       GTMTimeValToNSTimeInterval(GTMBootTimeRelativeTo1970());
   return [NSDate dateWithTimeIntervalSince1970:ti];