Linux Process Management

Linux Process Management(12) >             the child either calls exec() or exits.
>          2. The child is not allowed to write to the address space.
>          3. ==> use fork() is ok in kernel > 2.2.
>   10. P.25 The Linux Implementation of Threads
>          1. The Linux kernel done not provide any special scheduling
>             semantics or data structures to represent threads.
>             Instead, a thread is merely a process which share certain
>             resources. Each thread has a unique task_struct and
>             appears to the kernel as a normal process which shares the
>             address space, filesystem resources, file descriptors, and
>             installed signal handlers.
>          2. Threads are created like normal task with the exception
>             that the clone() system call is passed flags corresponding
>             to specific resources to be shared:
>             clone (CLONE_VM CLONE_FS CLONE_FILES CLONE_SIGHAND, 0);
>             fork() can be implemented by clone() as:
>             clone (SIGCHLD, 0);