Platform SDK: Win32 API |
Locks the logical volume.
mov ax, 440Dh ; generic IOCTL mov bh, LockLevel ; see below mov bl, DriveNum ; see below mov ch, DeviceCat ; see below mov cl, 4Ah ; Lock Logical Volume mov dx, Permissions ; see below int 21h jc error_handler
Value | Description |
---|---|
08h | FAT32, FAT16, or FAT12 drive. |
48h | FAT32, FAT16, or FAT12 drive. This value is supported on Windows 95 OEM Service Release 2 and later. |
Note: Because this call may be implemented in the device driver, the 48h form of this call may fail on FAT16 or FAT12 media. Therefore, applications making the 48h form of this call must fall back on the 08h form if the 48h call fails.
Bit | Meaning |
---|---|
0 | 0 = Write operations are failed (specified when a level 1 lock is obtained). |
0 | 1 = Write operations are allowed (specified when a level 1 lock is obtained). |
1 | 0 = New file mapping are allowed (specified when a level 1 lock is obtained). |
1 | 1 = New file mapping are failed (specified when a level 1 lock is obtained). |
2 | 1 = The volume is locked for formatting (specified when a level 0 lock is obtained for the second time). |
Clears the carry flag if successful. Otherwise, the function sets the carry flag and sets the AX register to an error value.
The volume must be locked before the application performs direct disk write operations by using Interrupt 26h or the IOCTL control functions. Lock Physical Volume (Interrupt 21h Function 440Dh Minor Code 4Bh) is used instead of this function before a call to an Interrupt 13h function. You must use Unlock Logical Volume (Interrupt 21h Function 440Dh Minor Code 6Ah) to release the lock.