Platform SDK: Win32 API

Exclusive Volume Locking Reference

The following functions can be used to manage exclusive volume locking.

Function Description
Interrupt 21h Function 440Dh Minor Code 4Ah Lock Logical Volume
Interrupt 21h Function 440Dh Minor Code 4Bh Lock Physical Volume
Interrupt 21h Function 440Dh Minor Code 6Ah Unlock Logical Volume
Interrupt 21h Function 440Dh Minor Code 6Bh Unlock Physical Volume
Interrupt 21h Function 440Dh Minor Code 6Ch Get Lock Flag State
Interrupt 21h Function 440Dh Minor Code 6Dh Enumerate Open Files
Interrupt 21h Function 440Dh Minor Code 6Eh Find Swap File
Interrupt 21h Function 440Dh Minor Code 70h Get Current Lock State
Interrupt 21h Function 710Dh Reset Drive

The exclusive-volume locking IOCTL functions are similar to other MS-DOS functions. An application must copy function parameters to registers and issue an Interrupt 21h instruction to carry out the call.