REBOOT(2) System Calls Manual REBOOT(2)
reboot - reboot system or halt processor
reboot(howto, [ bootargs ] )
reboot() reboots the system, and is invoked automatically in the event
of unrecoverable system failures. howto is a mask of options passed to
the bootstrap program. The system call interface permits only RB_HALT
or RB_AUTOBOOT to be passed to the reboot program; the other flags are
used in scripts stored on the console storage media, or used in manual
bootstrap procedures. When none of these options (for instance
RB_AUTOBOOT) is given, the system is rebooted from file /vmunix 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 then normally per-
The bits of howto are:
RB_HALT the processor is simply halted; no reboot takes place.
RB_HALT should be used with caution.
RB_ASKNAME Interpreted by the bootstrap program itself, causing it
to inquire as to what file should be booted. Normally,
the system is booted from the file /vmunix without ask-
RB_SINGLE Normally, the reboot procedure involves an automatic
disk consistency check and then multi-user operations.
RB_SINGLE prevents the consistency check, rather simply
booting the system with a single-user shell on the con-
sole. RB_SINGLE is interpreted by the init(8) program
in the newly booted system.
RB_DUMP A system core dump is performed before rebooting.
RB_STRING The optional argument bootargs is passed to the boot-
strap program. See boot(8S) for details. This option
overrides RB_SINGLE but the same effect can be achieved
by including -s as an option in bootargs.
Only the super-user may reboot() a machine.
On success, reboot() does not return. On failure, it returns -1 and
sets errno to indicate the error.
EPERM The caller is not the super-user.
panic(8S), halt(8), init(8), intro(8), reboot(8)
21 January 1990 REBOOT(2)