why there're lots of child processes when fork?

iclinux · 01-17-2005, 05:23 AM

When I create a child process that consists of multiple threads, I'll find lots of child processes in the system.

Can you tell me why, or how to solve this problem?

Regards.

Code:

pid_t spawn(const char *program, char *const arg_list[])
{   
    assert(program && arg_list);
    
    // Duplicate this process.
    pid_t children_pid = fork();
    if (children_pid != 0) { // This is the parent process.
        return children_pid;
    } else {                 // This is the child process
        // Now execute PROGRAM
        execv(program, arg_list);
        
        // The execvp function returns only if an error occurs
        fprintf(stderr, "Error occurred in spawn()'s execvp. "
                        "[Bad parameter, or Has no root privilege]\n");
        abort(); // Abort the child process, no surprise here!
    }
}

Hko · 01-17-2005, 11:12 AM

In Linux, threads are implemented as a special form of processes (lightweight and sharing data).

I think what you see as processes are actually the threads.

May I recommend

Code:

perror("spawn(), execv()");

instead of:

Code:

fprintf(stderr, "Error occurred in spawn()'s execvp. "
                        "[Bad parameter, or Has no root privilege]\n");

Using perror(), you'll get more specific information in case of an error.

iclinux · 01-17-2005, 06:53 PM

hello Hko,
I'll accept your advice.
and thank you very much

But my child process has about 100 threads, it's boring to see about 100 child process name in the system after forked.
There's no method to solve this?

Quote:

Originally posted by Hko
In Linux, threads are implemented as a special form of processes (lightweight and sharing data).

I think what you see as processes are actually the threads.

May I recommend

Code:

perror("spawn(), execv()");

instead of:

Code:

fprintf(stderr, "Error occurred in spawn()'s execvp. " "[Bad parameter, or Has no root privilege]\n");

Using perror(), you'll get more specific information in case of an error.

iclinux · 01-18-2005, 07:09 AM

can't be solved?