new

static VALUE
esignal_init(int argc, VALUE *argv, VALUE self)
{
    int argnum = 1;
    VALUE sig = Qnil;
    int signo;
    const char *signm;

    if (argc > 0) {
        sig = rb_check_to_integer(argv[0], "to_int");
        if (!NIL_P(sig)) argnum = 2;
        else sig = argv[0];
    }
    rb_check_arity(argc, 1, argnum);
    if (argnum == 2) {
        signo = NUM2INT(sig);
        if (signo < 0 || signo > NSIG) {
            rb_raise(rb_eArgError, "invalid signal number (%d)", signo);
        }
        if (argc > 1) {
            sig = argv[1];
        }
        else {
            sig = rb_signo2signm(signo);
        }
    }
    else {
        int len = sizeof(signame_prefix);
        if (SYMBOL_P(sig)) sig = rb_sym2str(sig); else StringValue(sig);
        signm = RSTRING_PTR(sig);
        if (strncmp(signm, signame_prefix, len) == 0) {
            signm += len;
            len = 0;
        }
        signo = signm2signo(signm);
        if (!signo) {
            rb_raise(rb_eArgError, "unsupported name `%.*s%"PRIsVALUE"'",
                     len, signame_prefix, sig);
        }
        sig = rb_sprintf("SIG%s", signm);
    }
    rb_call_super(1, &sig);
    rb_iv_set(self, "signo", INT2NUM(signo));

    return self;
}