CALL instruction application programming interface (API)

This information describes the CALL instruction API for TCP⁄IP application programs written in the COBOL, PL/I, or System/370 Assembly 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.
For a PL/I program, include the following statement before your first call instruction.
```
  DCL EZASOKET ENTRY OPTIONS(ASM,INTER) EXT;
```
If you use the CALL instruction from code that will run as a part of a CICS transaction, see the z/OS Communications Server: IP CICS Sockets Guide for additional considerations.
The Sockets Extended module (EZASOKET) is located in the hlq.SEZATCP(EZASOKET) load module and should be resolved from there when it is processed by the binder. You can use the linkage editor MAP parameter to produce the module map report to verify where EZASOKET is resolved.