Interrupt 2Fh Function 1681h

mov ax, 1681h ; Begin Critical Section

int 2Fh ; multiplex interrupt

Begin Critical Section (Interrupt 2Fh Function 1681h) prevents Windows from switching execution from the current VM to some other. MS-DOS device drivers and TSRs use this function to prevent a task-switch from occurring.

Parameters

This function has no parameters.

Return Value

This function has no return value.

Comments

When a virtual machine is in a critical section, no other task will be allowed to run except to service hardware interrupts. For this reason, the critical section should be released using End Critical Section (Interrupt 2Fh Function 1682h) as soon as possible.

See Also

Interrupt 2Fh Function 1682h End Critical Section