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RedHat 9 (Linux i386) - man page for reboot (redhat section 2)

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REBOOT(2)			    Linux Programmer's Manual				REBOOT(2)

       reboot - reboot or enable/disable Ctrl-Alt-Del

       For  libc4  and libc5 the library call and the system call are identical, and since kernel
       version 2.1.30 there are symbolic names LINUX_REBOOT_* for  the	constants  and	a  fourth
       argument to the call:

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

       int reboot(int magic, int magic2, int flag, void *arg);

       Under  glibc  some  of  the  constants  involved  have gotten symbolic names RB_*, and the
       library call is a 1-argument wrapper around the 3-argument system call:

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

       int reboot(int flag);

       The reboot call reboots the system, or enables/disables the reboot keystroke  (abbreviated
       CAD, since the default is Ctrl-Alt-Delete; it can be changed using loadkeys(1)).

       This system call will fail (with EINVAL) unless magic equals LINUX_REBOOT_MAGIC1 (that is,
       0xfee1dead) and magic2 equals LINUX_REBOOT_MAGIC2 (that is,  672274793).   However,  since
       2.1.17	also   LINUX_REBOOT_MAGIC2A   (that   is,   85072278)	and   since  2.1.97  also
       LINUX_REBOOT_MAGIC2B (that is, 369367448) are permitted as value for magic2.   (The  hexa-
       decimal values of these constants are meaningful.)  The flag argument can have the follow-
       ing values:

	      (RB_AUTOBOOT, 0x1234567).  The message  `Restarting  system.'  is  printed,  and	a
	      default  restart is performed immediately.  If not preceded by a sync(2), data will
	      be lost.

	      (RB_HALT_SYSTEM, 0xcdef0123;  since  1.1.76).   The  message  `System  halted.'  is
	      printed,	and  the system is halted.  Control is given to the ROM monitor, if there
	      is one.  If not preceded by a sync(2), data will be lost.

	      (0x4321fedc; since 2.1.30).  The message `Power down.' is printed,  the  system  is
	      stopped, and all power is removed from the system, if possible.  If not preceded by
	      a sync(2), data will be lost.

	      (0xa1b2c3d4; since 2.1.30).  The message `Restarting system with command	'%s''  is
	      printed, and a restart (using the command string given in arg) is performed immedi-
	      ately.  If not preceded by a sync(2), data will be lost.

	      (RB_ENABLE_CAD, 0x89abcdef).  CAD is enabled.  This means that  the  CAD	keystroke
	      will immediately cause the action associated to LINUX_REBOOT_CMD_RESTART.

	      (RB_DISABLE_CAD,	0).   CAD  is  disabled.   This means that the CAD keystroke will
	      cause a SIGINT signal to be sent to init (process 1), whereupon  this  process  may
	      decide upon a proper action (maybe: kill all processes, sync, reboot).

       Only the super-user may use this function.

       The  precise effect of the above actions depends on the architecture.  For the i386 archi-
       tecture, the additional argument does not do anything at present (2.1.122), but	the  type
       of  reboot  can be determined by kernel command line arguments (`reboot=...') to be either
       warm or cold, and either hard or through the BIOS.

       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

       EINVAL Bad magic numbers or flag.

       EPERM  A non-root user attempts to call reboot.

       reboot is Linux specific, and should not be used in programs intended to be portable.

       sync(2), bootparam(7), ctrlaltdel(8), halt(8), reboot(8)

Linux 2.1.122				    1998-09-24					REBOOT(2)
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