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ACMDM_DRIVER_ABOUT (Compact 2013)

  • Article

3/26/2014

This message requests an ACM driver to display its About dialog box.

Parameters

  • dwDeviceID
    Value that specifies a driver instance identifier. The driver returns this value in response to the ACM_Open (ACM Driver) function.
  • hDriver
    Handle to a driver.
  • uMsg
    Value that specifies this message.
  • lParam1
    Value that contains a validated window handle, which the driver should use to specify the parent window for the About dialog box. The value also can be -1L.
  • lParam2
    Not used.

Return Values

MMSYSERR_NOERROR indicates success. Otherwise, the driver returns one of the MMSYSERR error values declared in the Mmsystem.h header file or one of the ACMERR error values declared in the Msacm.h header file. If the driver does not provide an About dialog box, it returns MMSYSERR_NOTSUPPORTED.

Remarks

The ACM (Waveapi.dll) sends this message by calling the ACM driver's ACM_IOControl function entry point through the DeviceIoControl function.

If an ACM driver provides an About dialog box, it displays the box in response to this message. If an ACM driver does not provide an About dialog box, it returns MMSYSERR_NOTSUPPORTED. In the latter case, the ACM displays a default About dialog box.

However, if lParam1 is -1L, the driver does not display its About dialog box. Instead, it returns MMSYSERR_NOERROR if it provides an About dialog box and MMSYSERR_NOTSUPPORTED if it does not provide an About dialog box.

Requirements

Header

msacmdrv.h

See Also

Reference

ACM Driver Messages
ACM_IOControl