sigsend, sigsendset --
send a signal to a process or a group of processes
cc . . . -lc
int sigsend(idtype_t idtype, id_t id, int sig);
int sigsendset(const procset_t *psp, int sig);
send a signal to processes
send a signal to processes
sigsend sends a signal to the process or group of
processes specified by id and idtype. The signal
to be sent is specified by sig and is either zero or one
of the values listed in
If sig is zero (the null signal), error checking is
performed but no signal is actually sent. This value can be used to
check the validity of id and idtype.
In order to send the signal to the target process (pid),
the sending process must have permission to do so, subject to the
real or effective user ID of the sending process matching
the real or saved (from
user ID of the receiving process, unless the sending
process is the superuser, or sig is SIGCONT and
the sending process has the same session ID as the
idtype and id interact as follows:
The process with a process ID of 0 is always excluded. The
process with a process ID of 1 is excluded unless
idtype is equal to P_PID.
If idtype is P_PID, sig is sent to the
process with process ID id.
If idtype is P_PGID, sig is sent to
any process with process group ID id.
If idtype is P_SID, sig is sent to any
process with session ID id.
If idtype is P_UID, sig is sent to any
process with effective user ID id.
If idtype is P_GID, sig is sent to any
process with effective group ID id.
If idtype is P_CID, sig is sent to any
process with scheduler class ID id.
If idtype is P_ALL, sig is sent to all
processes and id is ignored.
If id is P_MYID, the value of id is
taken from the calling process.
sigsendset provides an alternate interface for sending
signals to sets of processes. This function sends signals to the set
of processes specified by psp. psp is a pointer
to a structure of type procset_t, defined in
<sys/procset.h>, which includes the following members:
p_lid specify the ID
type and ID of one (``left'') set of processes;
p_rid specify the ID
type and ID of a second (``right'') set of
processes. ID types and IDs are specified just
as for the idtype and id arguments to
p_op specifies the operation to be
performed on the two sets of processes to get the set of processes
the system call is to apply to. The valid values for
and the processes they specify are:
set difference: processes in left set and not in right set
set intersection: processes in both left and right sets
set union: processes in either left or right set or both
set exclusive-or: processes in left or right set but not in both
On success, sigsend and sigsendset return 0. On
failure, sigsend and sigsendset return -1 and
set errno to identify the error.
In the following conditions, sigsend and
sigsendset fail and set errno to:
In addition, sigsendset fails if:
sig is not a valid signal number.
idtype is not a valid idtype field.
sig is SIGKILL, idtype is
P_PID and id is 1 (proc1).
The calling process is not the superuser, the real or effective user
ID of the sending process does not match the real or
effective user ID of the receiving process, and the
calling process is not sending SIGCONT to a process that
shares the same session.
No process can be found corresponding to that specified by
id and idtype.
psp points outside the process' allocated address space.
sigsend and sigsendset are conformant with:
AT&T SVID Issue 3.
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003