Hi, I want to use clone() system call with CLONE_PARENT & CLONE_THREAD flags. But when I compile, I get error saying, these flags are not defined. These flags are introdused from 2.4 kernel. I have redhat 7.1. But the /usr/include/bits/sched.h does not define these flags. Can anyone please tell me which version of libc I have to install inorder to use these flags. Please tell me from where to get this & how to install. Also, what is use of CLONE_THREAD? I read that it creates child with same thread group id. where can I find more info about this linux thread group? Regards, Saji -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/