CALL instruction API

This topic describes the CALL instruction API for TCP⁄IP application programs written in the COBOL, PL/I, or System/370 Assembler language. The format and parameters are described for each socket call.

Note:

Unless your program is running in a CICS® environment, reentrant code and multithread applications are not supported by this interface.
Only one copy of an interface can exist in a single address space.
For a PL/I program, include the following statement before your first call instruction.
```
 DCL EZASOKET ENTRY OPTIONS(ASM,INTER) EXT;
```
The entry point for the CICS Sockets Extended module (EZASOKET) is within the hlq.SEZATCP(EZACICAL) load module and should be resolved from there when processed by the binder. Therefore, EZACICAL should be included explicitly in your link-editing JCL. If not included, you could experience problems, such as the CICS region waiting for the socket calls to complete. You can use the linkage editor MAP parameter to produce the module map report to verify where EZASOKET is resolved.
See Figure 1.

If you do not want to explicitly include EZACICAL in your link-edit JCL then you can use the EZACICSO CICS Sockets Extended module. The EZACICSO CICS Sockets Extended module is an ALIAS for EZASOKET that resides in the same entry point in EZACICAL as EZASOKET. You must also substitute any "CALL EZASOKET" invocations in your program with "CALL EZACICSO". This allows you to use the Binder's Automatic Library Call option (AUTOCALL) to build your load modules.

SEZATCP load library data set needs to be included in the SYSLIB DD concatenation.