NAME

       reboot — reboot system or halt processor

LIBRARY

       Standard C Library (libc, -lc)

SYNOPSIS

       #include <unistd.h>
       #include <sys/reboot.h>

       int
       reboot(int howto);

DESCRIPTION

       The  reboot()  system  call  reboots  the  system.   Only  the super-user may reboot a machine on demand.
       However, a reboot is invoked automatically in the event of unrecoverable system failures.

       The howto argument is a mask of options; the system call interface allows the following options,  defined
       in  the  include  file  <sys/reboot.h>,  to  be  passed  to  the new kernel or the new bootstrap and init
       programs.

       RB_AUTOBOOT   The default, causing the system to reboot in its usual fashion.

       RB_ASKNAME    Interpreted by the bootstrap program itself, causing it to prompt on the console as to what
                     file should be booted.  Normally, the system is booted from the file “xx(0,0)kernel”, where
                     xx is the default disk name, without prompting for the file name.

       RB_DFLTROOT   Use the compiled in root device.  Normally, the system uses the device from  which  it  was
                     booted  as  the root device if possible.  (The default behavior is dependent on the ability
                     of the bootstrap program to determine the drive from which it  was  loaded,  which  is  not
                     possible on all systems.)

       RB_DUMP       Dump kernel memory before rebooting; see savecore(8) for more information.

       RB_HALT       the  processor  is  simply  halted; no reboot takes place.  This option should be used with
                     caution.

       RB_POWEROFF   After halting, the shutdown code will do what it can to turn off the power.  This  requires
                     hardware support.

       RB_INITNAME   An option allowing the specification of an init program (see init(8)) other than /sbin/init
                     to be run when the system reboots.  This switch is not currently available.

       RB_KDB        Load  the symbol table and enable a built-in debugger in the system.  This option will have
                     no useful function if the kernel is not configured for debugging.   Several  other  options
                     have different meaning if combined with this option, although their use may not be possible
                     via the reboot() system call.  See ddb(4) for more information.

       RB_NOSYNC     Normally,  the  disks  are sync'd (see sync(8)) before the processor is halted or rebooted.
                     This option may be useful if file  system  changes  have  been  made  manually  or  if  the
                     processor is on fire.

       RB_RDONLY     Initially  mount  the  root file system read-only.  This is currently the default, and this
                     option has been deprecated.

       RB_SINGLE     Normally, the reboot procedure involves an automatic disk consistency check and then multi-
                     user operations.  RB_SINGLE prevents this, booting the system with a single-user  shell  on
                     the  console.  RB_SINGLE is actually interpreted by the init(8) program in the newly booted
                     system.

       When no options are given (i.e., RB_AUTOBOOT is used), the system is rebooted from file “kernel”  in  the
       root  file system of unit 0 of a disk chosen in a processor specific way.  An automatic consistency check
       of the disks is normally performed (see fsck(8)).

RETURN VALUES

       If successful, this call never returns.  Otherwise, a -1 is returned and an  error  is  returned  in  the
       global variable errno.

ERRORS

       [EPERM]            The caller is not the super-user.

SEE ALSO

       crash(8), halt(8), init(8), reboot(8), savecore(8)

HISTORY

       The reboot() system call appeared in 4.0BSD.

BUGS

       The HP300 implementation supports neither RB_DFLTROOT nor RB_KDB.

Debian                                            June 4, 1993                                         REBOOT(2)