Add a method to reset the device

This basically acts as if the app created a new context with the specified
attributes (causing the device to reset with new parameters), then immediately
delete it. Existing contexts remain undisturbed, except for a temporary pause
while the device output is reconfigured.

Alc/ALc.c

@@ -162,6 +162,8 @@ static const ALCfunction alcFunctions[] = {
 
     DECL(alcGetInteger64vSOFT),
 
+    DECL(alcResetDeviceSOFT),
+
     DECL(alEnable),
     DECL(alDisable),
     DECL(alIsEnabled),
@@ -3289,6 +3291,42 @@ ALC_API ALCdevice* ALC_APIENTRY alcGetContextsDevice(ALCcontext *Context)
 }
 
 
+/* alcResetDeviceSOFT
+ *
+ * Resets the given device output, using the specified attribute list.
+ */
+ALC_API ALCboolean ALC_APIENTRY alcResetDeviceSOFT(ALCdevice *device, const ALCint *attribs)
+{
+    ALCenum err;
+
+    LockLists();
+    if(!(device=VerifyDevice(device)) || device->Type == Capture || !device->Connected)
+    {
+        UnlockLists();
+        alcSetError(device, ALC_INVALID_DEVICE);
+        if(device) ALCdevice_DecRef(device);
+        return ALC_FALSE;
+    }
+
+    if((err=UpdateDeviceParams(device, attribs)) != ALC_NO_ERROR)
+    {
+        UnlockLists();
+        alcSetError(device, err);
+        if(err == ALC_INVALID_DEVICE)
+        {
+            V0(device->Backend,lock)();
+            aluHandleDisconnect(device);
+            V0(device->Backend,unlock)();
+        }
+        ALCdevice_DecRef(device);
+        return ALC_FALSE;
+    }
+    UnlockLists();
+    ALCdevice_DecRef(device);
+
+    return ALC_TRUE;
+}
+
 /* alcOpenDevice
  *
  * Opens the named device.

OpenAL32/Include/alMain.h

@@ -49,6 +49,10 @@
 #define ALC_HRTF_REQUIRED_SOFT                   0x0003
 #define ALC_HRTF_HEADPHONES_DETECTED_SOFT        0x0004
 #define ALC_HRTF_UNSUPPORTED_FORMAT_SOFT         0x0005
+typedef ALCboolean (ALC_APIENTRY*LPALCRESETDEVICESOFT)(ALCdevice *device, const ALCint *attribs);
+#ifdef AL_ALEXT_PROTOTYPES
+ALC_API ALCboolean ALC_APIENTRY alcResetDeviceSOFT(ALCdevice *device, const ALCint *attribs);
+#endif
 #endif
 
 #ifndef ALC_SOFT_midi_interface