BOOT(9) | Kernel Developer's Manual | BOOT(9)

# NAME

`boot` — halt or reboot the system

# SYNOPSIS

`#include <sys/reboot.h>`

void
`boot`(int howto);

# DESCRIPTION

The `boot`() function handles final system shutdown, and either halts or reboots the system. The exact action to be taken is determined by the flags passed in howto and by whether or not the system has finished autoconfiguration.

If the system has finished autoconfiguration, `boot`() does the following:

1. Sets the boothowto system variable from the howto argument.
2. If this is the first invocation of `boot`() and the `RB_NOSYNC` flag is not set in howto, syncs and unmounts the system disks by calling `vfs_shutdown`() and sets the time of day clock by calling resettodr(9).
3. Disables interrupts.
4. If rebooting after a crash (i.e., if `RB_DUMP` is set in howto, but `RB_HALT` is not), saves a system crash dump.
5. Prints a message indicating that the system is about to be halted or rebooted.
6. If `RB_HALT` is set in howto, halts the system. Otherwise, reboots the system.

If the system has not finished autoconfiguration, `boot`() prints a message, and halts the system (unless `RB_USERREQ` is specified, in which case the system will be halted if `RB_HALT` is given, and rebooted otherwise; see reboot(2) for more details).

# SEE ALSO

reboot(2), resettodr(9)

December 10, 2014 | Debian