KTHREAD(9)                   OpenBSD Kernel Manual                  KTHREAD(9)

NAME
     kthread_create, kthread_exit, kthread_create_deferred - kernel threads.

SYNOPSIS
     #include <sys/kthread.h>

     int
     kthread_create(void (*func)(void), void *arg, struct proc **newpp,
             const char *fmt, ...);

     void
     kthread_exit(int ecode);

     void
     kthread_create_deferred(void (*func)(void), void *arg);

DESCRIPTION
     Kernel threads are system light-weight processes: cloned from process 0
     (the swapper), sharing its memory map and limits, but with a copy of its
     file descriptor table.  They don't receive broadcast nor group signals
     and they can't be swapped.

     Any process can call kthread_create() to create a kernel thread.  The new
     process starts up executing func with argument arg. If newpp is not NULL,
     it is filled with the address of the new process.  fmt and the remaining
     arguments are used to name the process.

     A kernel thread will terminate by calling kthread_exit(), with exit code
     ecode.

     Since the system has to be up and running for creating new processes, de-
     vice drivers that want to create kernel threads early (eg, at attach
     time) may use kthread_create_deferred() instead.  The system will call
     back the function func with argument arg when it can create threads, so
     it is up to func to call kthread_create() at that point.

SEE ALSO
     fork1(9)

BUGS
     There is currently no way to use ecode to any sensible purpose from
     kthread_exit().

OpenBSD 2.6                    September 1, 1999                             1
