system_kill Interface

system_kill(3f) - [M_system:SIGNALS] send a signal to a process or
                  a group of processes
(LICENSE:PD)

integer(kind=c_int) function system_kill(pid,sig)

   integer,intent(in) :: pid
   integer,intent(in) :: sig

The kill() function shall send a signal to a process or a group of
processes specified by pid. The signal to be sent is specified by
sig and is either one from the list given in <signal.h> or 0. If sig
is 0 (the null signal), error checking is performed but no signal
is actually sent. The null signal 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, unless the sending process has appropriate
privileges, the real or effective user ID of the sending process
shall match the real or saved set-user-ID of the receiving process.

If pid is greater than 0, sig shall be sent to the process whose
process ID is equal to pid.

If pid is 0, sig shall be sent to all processes (excluding an
unspecified set of system processes) whose process group ID is equal
to the process group ID of the sender, and for which the process has
permission to send a signal.

If pid is -1, sig shall be sent to all processes (excluding an
unspecified set of system processes) for which the process has
permission to send that signal.

If pid is negative, but not -1, sig shall be sent to all processes
(excluding an unspecified set of system processes) whose process
group ID is equal to the absolute value of pid, and for which the
process has permission to send a signal.

If the value of pid causes sig to be generated for the sending process,
and if sig is not blocked for the calling thread and if no other
thread has sig unblocked or is waiting in a sigwait() function for
sig, either sig or at least one pending unblocked signal shall be
delivered to the sending thread before kill() returns.

The user ID tests described above shall not be applied when sending
SIGCONT to a process that is a member of the same session as the
sending process.

An implementation that provides extended security controls may impose
further implementation-defined restrictions on the sending of signals,
including the null signal. In particular, the system may deny the
existence of some or all of the processes specified by pid.

The kill() function is successful if the process has permission to
send sig to any of the processes specified by pid. If kill() fails,
no signal shall be sent.

Upon successful completion, 0 shall be returned. Otherwise, -1 shall be
returned and errno set to indicate the error.

The kill() function shall fail if:

EINVAL  The value of the sig argument is an invalid or unsupported
        signal number.
EPERM   The process does not have permission to send the signal to
        any receiving process.
ESRCH   No process or process group can be found corresponding to
        that specified by pid. The following sections are informative.

program demo_system_kill
use M_system, only : system_kill
use M_system, only : system_perror
implicit none
integer           :: i,pid,ios,ierr,signal=9
character(len=80) :: argument

   do i=1,command_argument_count()
      ! get arguments from command line
      call get_command_argument(i, argument)
      ! convert arguments to integers assuming they are PID numbers
      read(argument,'(i80)',iostat=ios) pid
      if(ios.ne.0)then
         write(*,*)'bad PID=',trim(argument)
      else
         write(*,*)'kill SIGNAL=',signal,' PID=',pid
      ! send signal SIGNAL to pid PID
         ierr=system_kill(pid,signal)
      ! write message if an error was detected
         if(ierr.ne.0)then
            call system_perror('*demo_system_kill*')
         endif
      endif
   enddo
end program demo_system_kill

getpid(), raise(), setsid(), sigaction(), sigqueue(),