Interrupt 21h Function 440Dh Minor Code
70h
Retrieves the
current lock level and permissions on the specified drive.
mov ax, 440Dh
; generic IOCTL
mov bl, DriveNum
; see below
mov ch, 08h
; device category (must be 08h)
mov cl, 70h ; Get Current Lock State
int 21h
jc error
Parameters
DriveNum
Drive to
retrieve lock information about. This parameter can be 0 for the default drive,
1 for A, 2 for B, and so on.
Return Value
Clears the
carry flag and sets the AX and CX registers to these values if successful:
|
AX |
Current
lock level. It may be either 0, 1, 2
or 3. If the volume is not locked, AX contains - 1 |
|
CX |
Lock
permissions. The bits have the following form: |
|
Bit |
Meaning |
|
0 |
0 = Write
operations are failed. |
|
0 |
1 = Write
operations are allowed, unless they are blocked by the lock level. |
|
1 |
0 = New
file mapping are allowed, unless they are blocked by the lock level. |
|
1 |
1 = New
file mapping are failed. |
|
2 |
1 = The
volume is locked for formatting. |
Remarks
The lock
level and the permissions determine the kind of access processes other than the
lock owner have to the volume while it is locked. The following operations are
allowed by processes other than lock owner at each lock level:
|
Level |
Operations
|
|
0 |
Read
operations, write operations, and new file mappings are failed. |
|
1 |
Read
operations are allowed. Write operations and new file mappings are either
allowed or failed based on permissions. |
|
2 |
Read
operations are allowed. Write operations and new file mappings are either
failed or blocked based on permissions. |
|
3 |
Read
operations are blocked. Write operations and new file mappings are either
failed or blocked based on permissions. |