INT 21 - DOS Internal - RETURN CritSectFlag POINTER
|
Input |
DOS1 |
N |
DOS2 |
Y |
DOS3 |
Y |
DOS5 |
Y |
Output |
|
AX |
34h |
|
|
|
AX |
|
BX |
|
|
|
|
|
|
CX |
|
|
|
|
CX |
|
DX |
|
|
|
|
DX |
|
ES:DI |
|
Pointer
to InDOS Flag |
ES:BX |
Notes: * When the critical section flag is nonzero, code within DOS is
being executed. It is safe to enter DOS when both the
critical section flag and the critical error flag are zero.
* The critical error flag is the byte after the critical section
flag in DOS 2.x, and the byte BEFORE the critical section flag
in DOS 3.x (except COMPAQ DOS 3.0, where the critical error
flag is located 01AAh bytes BEFORE the critical section flag) |