CHECKPT(1)

NAME
checkpt - resume checkpointed program

SYNOPSIS
checkpt -r file.ckpt

DESCRIPTION
The checkpt utility will resume the checkpointed program from the specified checkpoint file. Programs can be checkpointed using ^E.

By default, only members of the wheel group can checkpoint a program. The group can be changed with the sysctl kern.ckptgroup. The checkpoint file template can be changed with the sysctl kern.ckptfile.

The checkpointing utility is fairly primitive. Only programs operating on normal files can be properly restored. Programs which operate on devices, sockets, or pipes (including piped commands) cannot be completely. File descriptors 0, 1, and 2, are not saved and the restored program will inherit the descriptors from checkpt.

Programs can actively support checkpointing by catching the SIGCKPT signal, cleaning up, and manually calling the sys_checkpoint() system call. The program can then choose whether to continue running or exit. The resumed program will get a (typically) positive return value from sys_checkpoint() which it can use to determine whether it just made the system call or whether it is being resumed from the system call. The program can then reconstruct non-checkpointed elements and resume.

SEE ALSO
stty(1), sys_checkpoint(2)

HISTORY
The checkpt command first appeared in DragonFly 1.0.