All processes have a processing environment (not to be confused with environment variables that are, as we will see, just one part of the processing environment). The processing environment consists of a unique set of information and conditions that is determined by the current state of the system and by the parent of the process. A process can access processing environment information and, in some cases, modify it. This is accomplished either directly or by using the appropriate system calls or library functions.
Programs and Processes
Remote Procedure Calls
Appendix A. Using Linux Manual Pages
Appendix B. UNIX Error Messages
Appendix C. RPC Syntax Diagrams
Appendix D. Profiling Programs