Z88 Developers' Notes
Contents   Contents of System Calls

GN_Uab, unlink an alarm block from the alarm chain

RST 20H, DEFW $6E09

IN: 

     BHL = extended pointer of alarm block
OUT, if call successful: 
     Fc = 0
     Fz = 1, Alarm block dequeued.
OUT, if call failed: 
     Fc = 1
     A = error code:
          RC_BAD ($04), bad arguments
Registers changed after return: 
     ..BCDEHL/IXIY same
     AF....../.... different
Notes:
The system only does limited error checking. If the alarm is done, the symbol counter is decremented, and the done flag is reset. If the alarm is pending it is cancelled,
Bugs:

Related calls:

GN_Aab, allocate alarm block
GN_Alp, process an expired alarm (internal OZ usage)
GN_Fab, free alarm block
GN_Lab, link an alarm block into the alarm chain
OS_Alm, alarm manipulation (internal OZ usage)