The MM_MIXM_LINE_CHANGE callback message notifies a client that the value of a mixer line item has changed.
Parameters
dwMsg
MM_MIXM_LINE_CHANGE
dwParam1
Line ID. Must match line ID value returned to the client in response to an MXDM_GETLINEINFO message.
dwParam2
NULL
Comments
A user-mode mixer driver sends an MM_MIXM_LINE_CHANGE message to its client, by means of a callback, when the value of a mixer line item has changed. The driver sends the message to the client by calling DriverCallback, passing the specified parameters.
The driver sends the MM_MIXM_LINE_CHANGE message only if the client has specified a notification target with the MXDM_OPEN message.
For kernel-mode drivers using soundlib.lib, this value is stored in a MIXER_DATA_ITEM structure and passed to the user-mode driver upon receipt of an IOCTL_MIX_REQUEST_NOTIFY control code.
For additional information, see Notifying Clients from Audio Drivers.