ACMDM_DRIVER_ABOUT
lParam1 = (LPARAM) hwndAbout // see below
lParam2 = reserved // should be ignored
Sent to an Audio Compression Manager (ACM) driver to allow the driver to display a custom About dialog box. This message is usually sent by the Control Panel Sound Mapper option to an ACM driver.
MMSYSERR_NOTENABLED | The driver failed to load or initialize. |
MMSYSERR_NOTSUPPORTED | The driver does not support a custom about box. |
An ACM driver can optionally support a custom About dialog box. To do so, return MMSYSERR_NOTSUPPORTED and allow a default dialog box to be displayed by the Control Panel Sound Mapper option.
If the driver supports a custom About dialog box, MMSYSERR_NOERROR should be returned. If lParam1 is equal to -1L, no dialog should be displayed because the driver is only being queried for support.
Note that the ACM will validate all parameters to this message before calling the driver. It is not necessary for the driver to validate the lParam1 and lParam2 parameters.
ACMDM_DRIVER_DETAILS, ACMDM_DRIVER_NOTIFY, ACMDM_HARDWARE_WAVE_CAPS_INPUT, ACMDM_HARDWARE_WAVE_CAPS_OUTPUT