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REBOOT(2)                   BSD System Calls Manual                  REBOOT(2)

NAME
     reboot -- reboot system or halt processor

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

     int
     reboot(int howto);

DESCRIPTION
     Reboot() reboots the system.  Only the super-user may reboot a machine on demand.  However, a reboot
     may be invoked automatically in the event of unrecoverable system failures.  Programs other than
     reboot(8) should not call reboot().  Shutdown(8) or a higher-level API will shut the system down
     cleanly.

     Howto 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)bsd'',
                   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_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() call.  See kadb(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 pro-cessor processor
                   cessor 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
                   ``bsd'' 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
     shutdown(8), halt(8), launchd(8), reboot(8)

BUGS
     The HP300 implementation supports neither RB_DFLTROOT nor RB_KDB.

HISTORY
     The reboot() function call appeared in 4.0BSD.

4th Berkeley Distribution        June 4, 1993        4th Berkeley Distribution