Communication Between Parent and Child Processes

• A call to pipe creates file descriptors, which are valid only within that process and its children.
• A process's file descriptors cannot be passed to unrelated processes; however, when the process calls fork, file descriptors are copied to the new child process. Thus, pipes can connect only related processes.
• In the following http://siber.cankaya.edu.tr/SystemsProgramming/cfiles/pipe.cprogram, (see Fig. 6.4.1) a fork spawns a child process. The child inherits the pipe file descriptors. The parent writes a string to the pipe, and the child reads it out.

  Figure 6.8: Using a Pipe to Communicate with a Child Process