ACMDM_STREAM_CLOSE (Windows Embedded CE 6.0)

1/6/2010

This message requests an ACM driver to close a conversion stream that was opened with an ACMDM_STREAM_OPEN message.

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
  Pointer to an ACMDRVSTREAMINSTANCE structure.

• 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. An asynchronous driver may have to return ACMERR_BUSY if a conversion operation has not completed.

Remarks

The ACM (Waveapi.dll) sends this message by calling the ACM driver's ACM_IOControl entry point through the DeviceIoControl function. The ACM sends this message when an application calls the acmStreamClose function. All ACM drivers that provide stream conversions must support this message.

If the driver supports asynchronous operations and the client has specified the ACM_STREAMOPENF_ASYNC flag, which is contained in the fdwOpen memberof ACMDRVSTREAMINSTANCE, the driver sends the client an MM_ACM_CLOSE callback message. It does this by calling the PostThreadMessage function after the operation completes.

Requirements

See Also

Reference

ACM_Open (ACM Driver)
ACMDRVSTREAMINSTANCE
ACM_IOControl

Concepts

ACM Driver Messages