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

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, char *bootstr);

DESCRIPTION

     reboot() 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.

     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.	In addition to the options described below, other options described in
     boothowto(9) may be set, but such options may be ignored by the system.

     Options can be combined together by OR'ing them, eg.  RB_DUMP | RB_NOSYNC would be interpreted as ``dump kernel memory before rebooting and
     don't sync the disks''.

     RB_AUTOBOOT     0x0000    The default, causing the system to reboot in its usual fashion.
     RB_ASKNAME      0x0001    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)netbsd'', where xx is the default disk name, without prompt-
			       ing for the file name.
     RB_DUMP	     0x0100    Dump kernel memory before rebooting; see savecore(8) for more information.
     RB_HALT	     0x0008    the processor is simply halted; no reboot takes place.  This option should be used with caution.
     RB_POWERDOWN    0x0808    This option is always used in conjunction with RB_HALT, and if the system hardware supports the function, the sys-
			       tem will be powered off, otherwise it has no effect.
     RB_INITNAME     0x0010    An option allowing the specification of an init program (see init(8)) other than /sbin/init to be run when the sys-
			       tem reboots.  This switch is not currently available.
     RB_KDB	     0x0040    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 ddb(4) for more information.
     RB_NOSYNC	     0x0004    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	     0x0080    Initially mount the root file system read-only.	This is currently the default, and this option has been depre-
			       cated.
     RB_SINGLE	     0x0002    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 inter-
			       preted 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 ``netbsd'' 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 nor-
			       mally performed (see fsck(8)).
     RB_STRING	     0x0400    bootstr is a string passed to the firmware on the machine, if possible, if this option is set.  Currently this is
			       only implemented on the sparc and the sun3 ports.
     RB_USERCONF     0x1000    Initially invoke the userconf(4) facility when the system starts up again, if it has been compiled into the kernel
			       that is loaded.

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

     ddb(4), crash(8), halt(8), init(8), reboot(8), savecore(8), boothowto(9)

HISTORY

     The reboot() function call appeared in 4.0BSD.

     The RB_DFLTROOT option is now obsolete.

BSD
								 September 4, 2009							       BSD