fork(), pipe() and exec() process creation and communication

Question

I have to write program that create process using pipe().

My first task is to write a parent process that generates four child processes using the

Answer 1

The exec family of functions is used to replace the current process with a new process. Note the use of the word replace. Once exec is called, the current process is gone and the new process starts. If you want to create a separate process, you must first fork, and then exec the new binary within the child process.

Using the exec functions is similar to executing a program from the command line. The program to execute as well as the arguments passed to the program are provided in the call to the exec function.

For example, the following execcommand^* is the equivalent to the subsequent shell command:

execl("/bin/ls", "/bin/ls", "-r", "-t", "-l", (char *) 0);

/bin/ls -r -t -l

_{* Note that "arg0" is the command/file name to execute}

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Since this is homework, it is important to have a good understanding of this process. You could start by reading documentation on pipe, fork, and exec combined with a few tutorials to gain a better understanding each step.

The following links should help to get you started:

• IBM developerWorks: Delve into UNIX process creation
• YoLinux Tutorial: Fork, Exec and Process control
• Pipe, Fork, Exec and Related Topics