This topic describes the C language API provided by CICS® TCP/IP and contain the following topics:

• C socket library lists the required header files and explains how to make them available to your programs.
• C socket compilation shows how to compile a C socket program that contains calls to sockets for CICS.
• Structures used in socket calls lists data structures used in C language socket calls.
• The ERRNO variable describes the use of a global variable used by the socket system to report errors.
• C socket call guidance describes the syntax and semantics of the socket calls and explains what they do and how they work together in the context of an application.
• Address Testing Macros describes the macros that is used to test special IPv6 addresses.