## Virtual Device Driver Reference for OS/2

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### VDHOpen - Purpose

Context Issues: This function can be called only in the DOS session-task context.

DOS Session Terminations: Any handles the virtual device driver opened for the terminating DOS session must be closed with VDHClose.

Notes: Using VDHOpen does not interfere with the handle space available to the DOS session with INT 21H, except that it does count against the system- wide limit on the number of open file handles. These VDHOpen handles and the handles returned from INT 21H $Open cannot be used interchangeably.