wait for all the child processes to finish

[kaka189]

hi all
i have a doubt..... wait system call will allow parent to wait till it's child finishes executing... how should we make a parent process which has many child's to wait till all of them finish their tasks??? plz explain me with a small example...
thanks in advance

[vijiambav]

one solution is when ever a fork() is executed, the return value from fork() to the parent i.e. PID of child is saved by the parent. Then call waitpid() specifying the child PID to block until child terminates. This way the parent knows which children have terminated and also whether all its children have terminated since it saved PIDs of all of its children. But I think this solution is laborious and time consuming.

[kyku]

Every time a child dies a SIGCHLD is delivered to the parent. Just keep a count on how many children you crated and decrement it in the signal handler. Should be working

[scm]

Surely you just wait in a loop until ECHILD is returned, meaning there are no more child processes to wait for.