DragonFly On-Line Manual Pages

CHECKPT(1)             DragonFly General Commands Manual            CHECKPT(1)

NAME
     checkpt -- resume checkpointed program

SYNOPSIS
     checkpt -r file.ckpt

DESCRIPTION
     The checkpt utility will resume the checkpointed program from the speci-
     fied 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 com-
     pletely.  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 sig-
     nal, 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.

DragonFly 3.5                  October 19, 2003                  DragonFly 3.5