ACMDM_DRIVER

ACMDM_DRIVER_ABOUT

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.

Return MMSYSERR_NOERROR if the operation is successful or an error value otherwise. The following errors are possible:

MMSYSERR_NOTENABLED	The driver failed to load or initialize.
MMSYSERR_NOTSUPPORTED	The driver does not support a custom about box.

lParam1

Handle to the window owner for the custom About dialog box. This parameter will be equal to -1L if the caller is only interested in whether a custom About dialog box is supported by the driver; no dialog box should be displayed. All other values should be used as the owner window handle for the dialog box (a NULL handle is valid).

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.

See also ACMDM_DRIVER_DETAILS, ACMDM_DRIVER_NOTIFY, ACMDM_HARDWARE_WAVE_CAPS_INPUT, ACMDM_HARDWARE_WAVE_CAPS_OUTPUT