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.
Requirements
** Windows NT/2000:** Requires Windows NT 3.1 or later.
** Windows 95/98:** Requires Windows 95 or later.
** Header:** Declared in Mmsystem.h.
See Also