call "CBL_MONITOR_OPEN_INTRA" using by reference monitor-handle
                              by value           open-flags 
               	 | Using call prototype (see Key) | Picture | |
|---|---|---|
| monitor-handle | cblt-pointer | usage pointer. | 
| open-flags | cblt-os-flags | pic x(4) comp-5 or pic x(8) comp-5 (64-bit native programs only) | 
| 0 | Readers and writers have interleaved priority; that is, if a write request is issued, any further read requests will block until the first write request is granted and finished | 
| 1 | Read requests always have priority, possibly leading to writer starvation. | 
Comments:
If open-flags bit 0 is set to 0, and nested read locks are requested, then single thread deadlock is possible.