NAME | SYNOPSIS | API RESTRICTIONS | DESCRIPTION | RETURN VALUES | ERRORS | ATTRIBUTES | SEE ALSO
#include <signal.h>int kill(pid_t pid, int sig);
The function or functions documented here may not be used safely in all application contexts with all APIs provided in the ChorusOS 5.0 product.
See API(5FEA) for details.
kill() sends the signal given by sig to pid, a process or a group of processes. sig may be one of the signals specified in sigaction(2POSIX) or it may be 0, in which case error checking is performed but no signal is actually sent. This can be used to check the validity of pid.
For a process to have permission to send a signal to a process designated by pid, the real or effective user ID of the receiving process must match that of the sending process, or the user must have appropriate privileges, such as those given by a set-user-ID program (alternatively, the user must be the super-user). A single exception is the signal SIGCONT
, which may always be sent to any descendant of the current process.
If pid is greater than zero, sig is sent to the process whose ID is equal to pid.
If pid is zero, sig is sent to all processes whose group ID is equal to the process group ID of the sender, and for which the process has permission.
If pid is -1 and the user has super-user privileges, the signal is sent to all processes excluding system processes and the process sending the signal. No error is returned if any process could be signaled.
If pid is -1 and the user is not the super-user, the signal is sent to all processes with the same uid as the user excluding the process sending the signal. No error is returned if any process could be signaled.
For compatibility with System V, if the process number is negative but not -1, the signal is sent to all processes whose process group ID is equal to the absolute value of the process number.
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error.
kill() will fail and no signal will be sent if:
sig is not a valid signal number.
No process can be found corresponding to that specified by pid.
The pid was given as 0 but the sending process does not have a process group.
The sending process is not the super-user and its effective user id does not match the effective user-id of the receiving process. When signaling a process group, this error is returned if any members of the group could not be signaled.
See attributes(5) for descriptions of the following attributes:
ATTRIBUTE TYPE | ATTRIBUTE VALUE |
---|---|
Interface Stability | Evolving |
MT-Level | Async-Signal-Safe |
NAME | SYNOPSIS | API RESTRICTIONS | DESCRIPTION | RETURN VALUES | ERRORS | ATTRIBUTES | SEE ALSO