Values returned in the range 0xFF00 through 0xFFFF are user-dependent error codes. Values returned in the range 0xFE00 through 0xFEFF are device-driver-dependent error codes.

This function provides a generic, expandable IOCtl facility.

A null (zero) value for pData specifies that this parameter is not defined for the generic IOCtl function being specified. A null value for pData causes the values passed in cbDataLenMax and pcbDataLen to be ignored.

A null (zero) value for pParams specifies that this parameter is not defined for the generic IOCtl function being specified. A null value for pParams causes the values passed in cbParmLenMax and pcbParmLen to be ignored.

The kernel formats a generic IOCtl packet and calls the device driver. Because OS/2 Version 1.0 and Version 1.1 device drivers do not understand generic IOCtl packets with cbDataLenMax, pcbDataLen, cbParmLenMax, and pcbParmLen, the kernel does not pass these fields to the device driver. Device drivers that are marked as level 2 or higher must support receipt of the generic IOCtl packets with associated length fields.

Do not pass a non-null pointer with a zero length.

See Generic IOCtl Commands for a complete listing of the generic IOCtl control functions (the IOCtl interface).

For debugging considerations, see DosDebug.