diff --git a/openbsc/src/ipaccess/ipaccess-proxy.c b/openbsc/src/ipaccess/ipaccess-proxy.c
index 21dc70c27..1dd5b8456 100644
--- a/openbsc/src/ipaccess/ipaccess-proxy.c
+++ b/openbsc/src/ipaccess/ipaccess-proxy.c
@@ -1076,7 +1076,7 @@ static void signal_handler(int signal)
 	}
 }
 
-static void print_help()
+static void print_help(void)
 {
 	printf(" ipaccess-proxy is a proxy BTS.\n");
 	printf(" -h --help. This help text.\n");
@@ -1090,7 +1090,7 @@ static void print_help()
 	printf(" -V --version. Print the version of OpenBSC.\n");
 }
 
-static void print_usage()
+static void print_usage(void)
 {
 	printf("Usage: ipaccess-proxy [options]\n");
 }