GN_Gab, Get first alarm block

Register parameters

RST 20H, DEFW $7E09

IN: - 
 
OUT, if call successful:
     Fc = 0
     BHL = first alarm block in list
 
OUT, if call failed:
     Fc = 1
     A = error code:
          RC_Fail, no existing alarm list
 
Registers changed after return:
     ...CDE../IXIY same
     AFB...HL/.... different

Notes

This is used by Alarm popdown to get the first alarm block and save alarms in a file. This system call is only available in OZ release V4.5 and newer.

Related calls

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