diff --git a/dlls/dinput/dinput_main.c b/dlls/dinput/dinput_main.c
index c461c073cf2..6ddcd71b203 100644
--- a/dlls/dinput/dinput_main.c
+++ b/dlls/dinput/dinput_main.c
@@ -233,7 +233,7 @@ static void _dump_EnumDevices_dwFlags(DWORD dwFlags) {
     TRACE("\n");
 }
 
-void _dump_diactionformatA(LPDIACTIONFORMATA lpdiActionFormat) {
+static void _dump_diactionformatA(LPDIACTIONFORMATA lpdiActionFormat) {
     unsigned int i;
 
     FIXME("diaf.dwSize = %d\n", lpdiActionFormat->dwSize);
diff --git a/dlls/dinput/dinput_private.h b/dlls/dinput/dinput_private.h
index 3c4776e7fc5..94b16a55a79 100644
--- a/dlls/dinput/dinput_private.h
+++ b/dlls/dinput/dinput_private.h
@@ -63,7 +63,6 @@ extern const struct dinput_device joystick_osx_device DECLSPEC_HIDDEN;
 extern void check_dinput_hooks(LPDIRECTINPUTDEVICE8W) DECLSPEC_HIDDEN;
 typedef int (*DI_EVENT_PROC)(LPDIRECTINPUTDEVICE8A, WPARAM, LPARAM);
 
-extern void _dump_diactionformatA(LPDIACTIONFORMATA) DECLSPEC_HIDDEN;
 extern void _copy_diactionformatAtoW(LPDIACTIONFORMATW, LPDIACTIONFORMATA) DECLSPEC_HIDDEN;
 extern void _copy_diactionformatWtoA(LPDIACTIONFORMATA, LPDIACTIONFORMATW) DECLSPEC_HIDDEN;