Compiling and binding

This section describes how to bind, load, and run z/OS® XL C programs containing z/OS UNIX sockets. This information is specific to the z/OS UNIX application program interface and assumes that you are familiar with the information on compiling and binding z/OS UNIX application programs in z/OS XL C/C++ Programming Guide and z/OS Language Environment Programming Guide. C++ programs can also use z/OS UNIX sockets, but C++ programs cannot use Berkley Sockets, they must always use X/Open Sockets.

You compile and bind your sockets application program in the same way as for any other C language program. The process is shown conceptually in Figure 1. You must make sure that the z/OS UNIX socket application programs have access to the files they need to compile and bind.

Figure 1. A conceptual overview of the compile, bind, and run steps

As shown, whether an application program's I/O request is targeted at the network (TCP/IP) or at a file, the z/OS UNIX logical file system (LFS) will route the request to the appropriate physical file system (PFS).

If your C language statements contain information, such as sequence numbers, which are not part of the input for the z/OS XL C compiler, you must include the following pragma directive in your program:

#pragma margins(1,72)

Note: In order to use AF_INET sockets, you must have release 3.1 or a later level of TCP/IP installed on your system. In order to use AF_INET6 sockets, you must have release z/OS V1R4 or later of TCP/IP installed on your system.