Hi, I am very new and have questions for the process control in Linux or Unix? What is the difference between a STOPPED process(signalled by SIGSTOP) and a sleeping process? I know I can continue a process by signaling SIGCONT, how to wake up a process from user-level? Is there posibble to pass parameters to signal handler? maybe one posibble way is to set a environment variable that can be catched by the signal-handler? Is there other way to do that, like passing arguments in function call? Thanks very much in advance. Noah -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/