CEE1000S 4093 90 CEE5101C BPX1MSS failed when using POSIX

Diagnosing The Problem

See Threadsafe restrictions for OPENAPI programs in the CICS information center for these details:

An OPENAPI program, although freed from the constraints imposed by the QR TCB, still has obligations both to the CICS system as a whole and to future users of the L8 or L9 TCB it is using.

The section further states:

At your own risk, if your OPENAPI program decides to use other (non CICS) APIs, you must be aware of the following:

• When invoking CICS services, or when returning to CICS, an OPENAPI program must ensure it restores the MVS programming environment as it was on entry to the program. This includes cross-memory mode, ASC mode, request block (RB) level, linkage stack level, TCB dispatching priority, in addition to cancelling any ESTAEs added.
  
• At CICS task termination, an OPENAPI program must ensure it leaves the open TCB in a state suitable to be reused by another CICS transaction. In particular, it must ensure that all non-CICS resources acquired specifically on behalf of the terminating task are freed. (see Threadsafe restrictions for OPENAPI programs section for full details)
  
• An OPENAPI program must not invoke under the L8 or L9 mode TCB a Language Environment program that is using MVS Language Environment services, because L8 and L9 mode TCBs are initialized for Language Environment using CICS services.