PL/I and C/370 compatibility

The following OS PL/I Version 2 Release 3 assembler user exits are supported for compatibility under z/OS® Language Environment®:

IBMBXITA (MVS Batch version)
IBMFXITA (CICS version)

For more information about IBMBXITA see PL/I for MVS & VM Compiler and Run-Time Migration Guide. These user exits are available only under C, not C++.

Default versions of the above exits are not supplied under z/OS Language Environment; instead, z/OS Language Environment supplies a default version of CEEBXITA. Table 1 describes the order of precedence if the IBMBXITA and IBMFXITA user exits are found in the same root program with CEEBXITA.

Table 1. Interaction of Assembler user exits
CEEBXITA Present	IBMBXITA Present under MVS Batch, IBMFXITA Present under CICS	Exit Driven
No	No	Default version of `CEEBXITA`
Yes	No	`CEEBXITA`
No	Yes	IBMBXITA under MVS Batch; IBMFXITA under CICS
Yes	Yes	`CEEBXITA`

CXIT_FUNC in IBMBXITA will map to CEEBXITA as follows:

CXIT_FUNC = 1 when IBMBXITA is invoked for initial enclave initialization or nested enclave initialization
CXIT_FUNC = 2 when IBMBXITA is invoked for initial enclave termination or nested enclave termination

CXIT_USERWD in IBMBXITA will persist across enclaves (for example, in system() calls).