z/VM: TCP/IP Programmer's Reference - z/VM - IBM

Chapter 1. General Programming InformationPorting ConsiderationsThis chapter contains fundamental, technical information that programmers needto know before they attempt to work with the application program interfaces (API)provided with TCP/IP.Important NoteIn order to develop or port applications in the C programming language thatinterface directly to TCP, UDP, and IP, or which modify TCP/IP for VM Ccomponents, the following are required:v IBM C for VM/ESA Compiler, Version 3 Release 1 (5654-033)v Language Environment, which is included in the base release.Accessing System Return MessagesTo access system return values while running your C program, use only theerrno.h include statement supplied with the compiler. To access TCP/IP networkreturn values, add the following include statement to your C program:#include Printing System Return MessagesTo print only system errors, use perror(), a procedure available in the C compilerrun-time library. To print both system and network errors, use tcperror(), aprocedure provided by IBM and included with TCP/IP Level 320 for VM.Compiling and Linking C ApplicationsThis section describes how to compile and link-edit C applications that use theTCP/IP C sockets1. Access the TCP/IP client minidisk (TCPMAINT 592) ahead of the S-disk toavoid conflicts with OpenEdition ® for VM/ESA.Establish the C development environment:– Access the C compiler– SET LDRTBLS 25 (the number you need depends on your program)– GLOBAL LOADLIB SCEERUNNote: CMSLIB is required only when the program will run in a 370-modevirtual machine.2. Compile your programs, ensuring that the preprocessor symbol VM isdefined. For example:CC myprog (DEF(VM)With OpenEdition for VM/ESA you can also use the c89 command and themake shell utility.© Copyright IBM Corp. 1987, 2001 1