winmm: Return error in waveOutMessage if either dwParam1 or dwParam2 is null.

dlls/winmm/tests/wave.c

@@ -1440,6 +1440,16 @@ static void wave_out_tests(void)
         ok((ndev == 0 && (preferred == -1 || broken(preferred != -1))) ||
                 preferred < ndev, "Got invalid preferred device: 0x%x\n", preferred);
 
+    rc = waveOutMessage((HWAVEOUT)WAVE_MAPPER, DRVM_MAPPER_PREFERRED_GET,
+         (DWORD_PTR)-1  , 0);
+    ok(rc == MMSYSERR_INVALPARAM || rc == MMSYSERR_BADDEVICEID, /* w2008+wvista */
+       "waveOutMessage(DRVM_MAPPER_PREFERRED_GET) failed: %u\n", rc);
+
+    rc = waveOutMessage((HWAVEOUT)WAVE_MAPPER, DRVM_MAPPER_PREFERRED_GET,
+         0, (DWORD_PTR)&status);
+    ok(rc == MMSYSERR_INVALPARAM || rc == MMSYSERR_BADDEVICEID, /* w2008+wvista */
+       "waveOutMessage(DRVM_MAPPER_PREFERRED_GET) failed: %u\n", rc);
+
     rc=waveOutGetDevCapsA(ndev+1,&capsA,sizeof(capsA));
     ok(rc==MMSYSERR_BADDEVICEID,
        "waveOutGetDevCapsA(%s): MMSYSERR_BADDEVICEID expected, got %s\n",

dlls/winmm/waveform.c

@@ -3262,17 +3262,17 @@ UINT WINAPI waveOutMessage(HWAVEOUT hWaveOut, UINT uMessage,
     case DRV_QUERYMAPPABLE:
         return MMSYSERR_NOERROR;
     case DRVM_MAPPER_PREFERRED_GET:
-        if(dwParam1) {
-            if(g_outmmdevices_count > 0)
-                /* Device 0 is always the default device */
-                *(DWORD *)dwParam1 = 0;
-            else
-                *(DWORD *)dwParam1 = -1;
-        }
+        if(!dwParam1 || !dwParam2)
+            return MMSYSERR_INVALPARAM;
 
-        if(dwParam2)
-            /* Status flags */
-            *(DWORD *)dwParam2 = 0;
+        if(g_outmmdevices_count > 0)
+            /* Device 0 is always the default device */
+            *(DWORD *)dwParam1 = 0;
+        else
+            *(DWORD *)dwParam1 = -1;
+
+        /* Status flags */
+        *(DWORD *)dwParam2 = 0;
 
         return MMSYSERR_NOERROR;
     }