sigsend(2)                                                          sigsend(2)


NAME
     sigsend, sigsendset - send a signal to a process or a group of processes

SYNOPSIS
     #include <sys/types.h>
     #include <sys/signal.h>
     #include <sys/procset.h>

     int sigsend(idtype_t idtype, id_t id, int sig);

     int sigsendset(procset_t *psp, int sig);

DESCRIPTION
     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 signal(5).  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 following ownership
     restrictions:

          The real or effective user ID of the sending process must match the
          real or saved [from exec(2)] user ID of the receiving process,
          unless the effective user ID of the sending process is super-user,
          or sig is SIGCONT and the sending process has the same session ID as
          the receiving process.

     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_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.

     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.

     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:


          idop_t       p_op;
          idtype_t     p_lidtype;
          id_t         p_lid;
          idtype_t     p_ridtype;
          id_t         p_rid;

     p_lidtype and p_lid specify the ID type and ID of one (``left'') set of
     processes; p_ridtype and 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 sigsend.  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 p_op and the processes
     they specify are:

     POP_DIFF      set difference: processes in left set and not in right set

     POP_AND       set intersection: processes in both left and right sets

     POP_OR        set union: processes in either left or right set or both

     POP_XOR       set exclusive-or: processes in left or right set but not in
                   both

     sigsend and sigsendset fail if one or more of the following are true:

     EINVAL         sig is not a valid signal number.

     EINVAL         idtype is not a valid idtype field.

     EPERM          sig is SIGKILL, idtype is P_PID and id is 1 (proc1).

     EPERM          The calling process does not have super-user privilege,
                    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.

     ESRCH          No process can be found corresponding to that specified by
                    id and idtype.

     In addition, sigsendset fails if:

     EFAULT         psp points outside the process's allocated address space.

SEE ALSO
     kill(1), getpid(2), getpgrp(2), kill(2), setpid(2), signal(2), signal(5)

DIAGNOSTICS
     On success, sigsend returns zero.  On failure, it returns -1 and sets
     errno to indicate the error.


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