| [EINVAL] |
| | The sig argument is not a valid signal number. |
| [ESRCH] |
| | No process can be found in the process group specified by pgrp. |
| [ESRCH] |
| | The process group was given as 0 but the sending process does not have a process group. |
| [EPERM] |
| | The sending process is not the super-user and one or more of the target processes has an effective user ID different from that of the sending process. |
|