Method: Process#kill

Defined in:
signal.c

#kill(signal, pid, ...) ⇒ Fixnum (private)

Sends the given signal to the specified process id(s) if pid is positive. If pid is zero signal is sent to all processes whose group ID is equal to the group ID of the process. signal may be an integer signal number or a POSIX signal name (either with or without a SIG prefix). If signal is negative (or starts with a minus sign), kills process groups instead of processes. Not all signals are available on all platforms.

pid = fork do
   Signal.trap("HUP") { puts "Ouch!"; exit }
   # ... do some work ...
end
# ...
Process.kill("HUP", pid)
Process.wait

produces:

Ouch!

If signal is an integer but wrong for signal, Errno::EINVAL or RangeError will be raised. Otherwise unless signal is a String or a Symbol, and a known signal name, ArgumentError will be raised.

Also, Errno::ESRCH or RangeError for invalid pid, Errno::EPERM when failed because of no privilege, will be raised. In these cases, signals may have been sent to preceding processes.

Returns:



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# File 'signal.c', line 384

VALUE
rb_f_kill(int argc, VALUE *argv)
{
#ifndef HAVE_KILLPG
#define killpg(pg, sig) kill(-(pg), (sig))
#endif
    int negative = 0;
    int sig;
    int i;
    volatile VALUE str;
    const char *s;

    rb_secure(2);
    rb_check_arity(argc, 2, UNLIMITED_ARGUMENTS);

    switch (TYPE(argv[0])) {
      case T_FIXNUM:
	sig = FIX2INT(argv[0]);
	break;

      case T_SYMBOL:
	s = rb_id2name(SYM2ID(argv[0]));
	if (!s) rb_raise(rb_eArgError, "bad signal");
	goto str_signal;

      case T_STRING:
	s = RSTRING_PTR(argv[0]);
      str_signal:
	if (s[0] == '-') {
	    negative++;
	    s++;
	}
	if (strncmp("SIG", s, 3) == 0)
	    s += 3;
	if ((sig = signm2signo(s)) == 0)
	    rb_raise(rb_eArgError, "unsupported name `SIG%s'", s);

	if (negative)
	    sig = -sig;
	break;

      default:
	str = rb_check_string_type(argv[0]);
	if (!NIL_P(str)) {
	    s = RSTRING_PTR(str);
	    goto str_signal;
	}
	rb_raise(rb_eArgError, "bad signal type %s",
		 rb_obj_classname(argv[0]));
	break;
    }

    if (argc <= 1) return INT2FIX(0);

    if (sig < 0) {
	sig = -sig;
	for (i=1; i<argc; i++) {
	    if (killpg(NUM2PIDT(argv[i]), sig) < 0)
		rb_sys_fail(0);
	}
    }
    else {
	const rb_pid_t self = (GET_THREAD() == GET_VM()->main_thread) ? getpid() : -1;
	int wakeup = 0;

	for (i=1; i<argc; i++) {
	    rb_pid_t pid = NUM2PIDT(argv[i]);

	    if ((sig != 0) && (self != -1) && (pid == self)) {
		int t;
		/*
		 * When target pid is self, many caller assume signal will be
		 * delivered immediately and synchronously.
		 */
		switch (sig) {
		  case SIGSEGV:
#ifdef SIGBUS
		  case SIGBUS:
#endif
#ifdef SIGKILL
		  case SIGKILL:
#endif
#ifdef SIGSTOP
		  case SIGSTOP:
#endif
		    ruby_kill(pid, sig);
		    break;
		  default:
		    t = signal_ignored(sig);
		    if (t) {
			if (t < 0 && kill(pid, sig))
			    rb_sys_fail(0);
			break;
		    }
		    signal_enque(sig);
		    wakeup = 1;
		}
	    }
	    else if (kill(pid, sig) < 0) {
		rb_sys_fail(0);
	    }
	}
	if (wakeup) {
	    rb_threadptr_check_signal(GET_VM()->main_thread);
	}
    }
    rb_thread_execute_interrupts(rb_thread_current());

    return INT2FIX(i-1);
}