The Linux Programming Interface

26MONITORING CHILD PROCESSES

In many application designs, a parent process needs to know when one of its child processes changes state—when the child terminates or is stopped by a signal. This chapter describes two techniques used to monitor child processes: the wait() system call (and its variants) and the use of the SIGCHLD signal.

26.1 Waiting on a Child Process

In many applications where a parent creates child processes, it is useful for the parent to be able to monitor the children to find out when and how they terminate. This facility is provided by wait() and a number of related system calls.

26.1.1 The wait() System Call

The wait() system call waits for one of the children of the calling process to terminate and returns the termination ...