diff --git a/src/core/main.c b/src/core/main.c
index b86e79a..27e61dd 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -16,7 +16,7 @@ enum event_loop_fd {
 
 static const char service_name[] = "org.freedesktop.impl.portal.desktop.wlr";
 
-int xdpw_usage(FILE* stream, int rc) {
+static int xdpw_usage(FILE* stream, int rc) {
 	static const char* usage =
 		"Usage: xdg-desktop-portal-wlr [options]\n"
 		"\n"