Question

int main()
{
    ...
    if(!fork())
        {
            execvp(cmdName,cmdParam);
        }
    printf("In main()...");
return(0);
}

1. Assuming I have correctly passed the cmdName & cmdParam arguments, how do I wait for the process created by execvp to finish, before resuming the execution of main()?
2. Does the execvp() create a process which is a child of the newly fork()ed process?

Answer 1

1. In the parent process, fork returns the PID of the child process, so you can store that in a variable, and then use waitpid to wait for the child process to terminate.

2. Not really – the new child process created by fork is a duplicate of the parent, and execvp then replaces its process image with a new image. Effectively you initially have two ‘copies’ of the parent, one of which then ‘becomes’ the new program.