wait()

A function that;

• Suspends execution until one of the child processes terminates
• Returns early if there is already a PID of a terminated child

pid_t wait(int* status)

• Returns the PID of the child or -1 if there are no child processes
• Writes to the status the exit() status of the child process

Example

pid_t child_pid, wpid;
int status = 0;
 
//Father code (before child processes start)
 
for (int id=0; id<n; id++) {
    if ((child_pid = fork()) == 0) {
        //child code
        exit(0);
    }
}
 
while ((wpid = wait(&status)) > 0); // this way, the father waits for all the child processes 
printf("%d", WEXITSTATUS(status)); // get the return code
 
//Father code (After all child processes end)

Exit Macros

• WIFEXITED()
• WEXITSTATUS()