HELP SYS_UNLOCK_HEAP                          Revised by Fran Evelyn, July 85

    sys_unlock_heap()

SYS_UNLOCK_HEAP reverses the effect of *SYS_LOCK_HEAP; that is, it 'unlocks'
the heap so that the next garbage collection includes the previously locked
area.

See also HELP
    *SYS_LOCK_HEAP   - locks the heap
    *SYSGARBAGE      - causes a garbage collection
    *POPMEMLIM       - on setting the maximum memory size
    *POPGCRATIO      - helps control determination of memory allocation
    *POPMEMUSED      - holds total memory used at last garbage collection
    *POPGCTIME       - holds the CPU time spent on garbage collections