diff --git a/tests/pkd/pkd_daemon.c b/tests/pkd/pkd_daemon.c
index 6c9c3592..55f7cc62 100644
--- a/tests/pkd/pkd_daemon.c
+++ b/tests/pkd/pkd_daemon.c
@@ -72,7 +72,8 @@ static void pkd_sighandler(int signum) {
     (void) signum;
 }
 
-static int pkd_init_libssh() {
+static int pkd_init_libssh(void)
+{
     int rc = ssh_threads_set_callbacks(ssh_threads_get_pthread());
     return (rc == SSH_OK) ? 0 : 1;
 }
@@ -115,7 +116,8 @@ out:
     return rc;
 }
 
-static int pkd_accept_fd() {
+static int pkd_accept_fd(void)
+{
     int fd = -1;
     struct sockaddr_in addr;
     socklen_t len = sizeof(addr);