DRV_OPEN

Directs the driver to open an new instance.

Parameters

dwDriverId

Identifier of the installable driver.

hdrvr

Handle of the installable driver instance.

lParam1

Address of a null-terminated, wide-character string that specifies configuration information used to open the instance. If no configuration information is available, either this string is empty or the parameter is NULL.

lParam2

32-bit driver-specific data.

Return Value

Returns a nonzero value if successful or zero otherwise.

Remarks

If the driver returns a nonzero value, the system uses that value as the driver identifier (the dwDriverId parameter) in messages it subsequently sends to the driver instance. The driver can return any type of value as the identifier. For example, some drivers return memory addresses that point to instance-specific information. Using this method of specifying identifiers for a driver instance gives the drivers ready access to the information while they are processing messages.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in mmsystem.h.