winmm: Check waveOutGetVolume parameter.

dlls/winmm/tests/wave.c

@@ -640,6 +640,9 @@ static void wave_out_test_deviceOut(int device, double duration,
     frag.dwFlags=0;
     frag.dwLoops=0;
 
+    rc=waveOutGetVolume(wout,0);
+    ok(rc==MMSYSERR_INVALPARAM,"waveOutGetVolume(%s,0) expected "
+       "MMSYSERR_INVALPARAM, got %s\n", dev_name(device),wave_out_error(rc));
     rc=waveOutGetVolume(wout,&volume);
     ok(has_volume ? rc==MMSYSERR_NOERROR : rc==MMSYSERR_NOTSUPPORTED,
        "waveOutGetVolume(%s): rc=%s\n",dev_name(device),wave_out_error(rc));

dlls/winmm/winmm.c

@@ -2425,7 +2425,12 @@ UINT WINAPI waveOutGetVolume(HWAVEOUT hWaveOut, LPDWORD lpdw)
 
     TRACE("(%p, %08lx);\n", hWaveOut, (DWORD)lpdw);
 
-     if ((wmld = MMDRV_Get(hWaveOut, MMDRV_WAVEOUT, TRUE)) == NULL)
+    if (lpdw == NULL) {
+        WARN("invalid parameter\n");
+        return MMSYSERR_INVALPARAM;
+    }
+
+    if ((wmld = MMDRV_Get(hWaveOut, MMDRV_WAVEOUT, TRUE)) == NULL)
         return MMSYSERR_INVALHANDLE;
 
     return MMDRV_Message(wmld, WODM_GETVOLUME, (DWORD_PTR)lpdw, 0L, TRUE);