Very Computer

Hi,

i want to write a little prog which executes another one using the execvp()
function. The executed program should be monitored and when it exits some
action should happen.
I wrote the following little code fragment which works very well so long
the executed prog does not fork into background, meaning that it exits its
parent process after forking.
So my question is:
Is there a way to trace the executed prog and/or to get the pid of the new
process if it forks into background?
If that can't be accomplished using plain c maybe it can be done using
the linux proc filesystem?

---<snip>---

pid_t childpid = fork();

switch( childpid ) {
        case -1:   /* fork failed */
            perror("fork(main)");
            exit( EXIT_FAILURE );
        case 0:    /* fork succeed - child process */
                execvp( argv_prog[0], argv_prog );
                // this point should never be reached
                perror("execvp(main)");
                exit( EXIT_FAILURE );
            break;
        default:   /* fork succeed - parent process */
            cout << "childprocess running" << endl;
            // wait until child exits
            int wait_result, status;
            waitpid( childpid, &status, WUNTRACED );
            cout << "childprocess exited" << endl;
            exit( EXIT_SUCCESS );
            break;

Quote:}

                                                                                                 arginfo.rm_pidfile_flag,
---<snap>---

-timo

--

| Timo Benk    
| Germany
| Registered Linux User #186431
| Fax/Voicemail:        +49/0180 505258732297

I am not sure what the problem with your code is. You can't easily
find out if a child's child dies, if that is what you mean. You
*could* maybe open a pipe, then the child will still have the pipe
open, the child's child will still have the pipe open. Then you can
select() on the pipe & when the pipe is invalid for writing (because
the child and grandchild have died.) the signal SIGPIPE will be
generated. I hope this helps.

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