sigsend, sigsendset - Send a signal to one or more processes
int sig ); int sigsendset(
const procset_t *psetp,
int sig );
Standard C Library (libc)
Specifies a process or group of processes to which a signal
is sent. Specifies how the id parameter is to be
interpreted. Specifies the signal to be sent. Points to
a procset_t structure that defines a set of processes.
The sigsend function sends a signal to a group of processes
specified by the id and idtype parameters. The sig
parameter specifies the signal to be sent. It contains
either a valid signal or a zero (0), which indicates that
no signal is to be sent, though the usual error checking
will still be performed.
To send the signal, the real or effective user IDs of the
sending process must match those of the receiving process,
unless the sending process has appropriate privileges, or
the sig parameter is SIGCONT and the receiving process is
in the same session as the sender.
The id and the idtype parameters together select the target
process(es) according to the following rules: If the
idtype parameter is set to P_PID, the target process is
the process whose process ID is equal to (pid_t)id. If
the idtype parameter is set to P_GID, the target processes
are those whose effective group ID is equal to (gid_t)id.
If the idtype parameter is set to P_UID, the target processes
are those whose effective user ID is equal to
(uid_t)id. If the idtype parameter is set to P_PGID, the
target processes are those whose process group ID is equal
to (pid_t)id. If the idtype parameter is set to P_SID,
the target processes are those whose session ID is equal
to (pid_t)id. If the idtype parameter is set to P_PPID,
sig is sent to all children of id. If the idtype parameter
is set to P_CID, sig is sent to any process whose
scheduling class ID is equal to id. If the idtype parameter
is set to P_ALL, all eligible processes are targets of
this operation, and id is ignored. If the id parameter is
set to P_MYID, the value used for id is taken from the
The process having a process ID of (pid_t)0 is never a
target, and the process with a process ID of (pid_t)1 is
targeted only if the idtype parameter is equal to P_PID.
In addition, certain system processes may not be signalled.
The sigsendset function allows sending to a set of processes
that is constructed by a boolean logic operation
performed on two sets of potential target processes
defined as described above for sigsend.
For the sigsendset function, the psetp parameter points
the procset_t structure. This structure is described in
detail on the procset(4) reference page.
Upon successful completion, both functions return the
value zero (0). Otherwise, a value of -1 is returned, and
errno is set to indicate the error.
If any of the following conditions occur, the sigsend or
sigsendset function sets errno to the corresponding value:
The value specified by the idtype parameter is not valid.
The value specified by the sig parameter is not zero and
is not a valid signal. The sig parameter is set to
SIGKILL, the idtype parameter is set to P_PID, and the id
parameter is set to the process ID of a special system
process. The id parameter specifies the process ID of a
special system process. Either the id parameter of the
sigsend function, or the p_lid or p_rid members of the
structure pointed at by the psetp parameter for the
sigsendset function are out-of-range. The calling process
lacks sufficient privilege, the real or effective user IDs
do not match, and this invocation is not sending SIGCONT
to a process in the same session. The processes specified
by the id and idtype, or the psetp parameters do not
Functions: kill(2), setpgid(2), setsid(2), sigaction(2)
Files: procset(4), signal(4)
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