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DRV_OPEN (Compact 2013)

  • Article

3/26/2014

This message requests a driver to be opened. Drivers are opened for many reasons. The most common reason is preparation for data conversion. Your driver must be able to handle multiple open-driver instances correctly. Multiple streams can and will be opened on a single driver instance. Do not store and/or create instance data that is unique to a stream.

Parameters

  • hdrvr
    Driver handle that will be returned to the application. This is typically the handle of the ACM driver, but this is not guaranteed. For example, if an ACM driver is implemented within a waveform driver, then the driver will be opened by both MMSYSTEM and ACM.
  • lParam2
    Pointer to the ACMDRVOPENDESC structure that defines how ACM driver is being opened.

Return Values

The supporting function returns zero (0) if the driver fails to open. Otherwise, it returns a nonzero value that identifies the driver instance

Remarks

Whenever an application sends a message to the driver, the Real-time Communications (RTC) Client API routes the message to this entry point and passes this value in the dwID parameter.

Requirements

Header

msacmdrv.h

See Also

Reference

ACM Driver Messages
DRV_CLOSE