Howto ruby custom exception using the C-API

Hello,

I create the following code to create a custom exception
using *three* parameter to initialize.

Q: is this code ok?

Thanks for help...

···

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#include "msgque_ruby.h"

static VALUE cMqSException;

static ID id_new;
static ID id_num;
static ID id_code;
static ID id_txt;

void NS(MqSException_Raise) (struct MqS* mqctx) {
  MQ_INT num = MqErrorGetNumI (mqctx);
  MQ_INT code = MqErrorGetCodeI (mqctx);
  MQ_CST text = MqErrorGetText (mqctx);

  VALUE exc = rb_funcall(cMqSException, id_new,
    3, INT2NUM(num), INT2NUM(code), rb_str_new2(text)
  );

  rb_exc_raise(exc);
}

static VALUE initialize(VALUE self, VALUE num, VALUE code, VALUE txt)
{
  rb_ivar_set(self, id_num, num);
  rb_ivar_set(self, id_code, code);
  rb_ivar_set(self, id_txt, txt);
  return self;
}

void NS(MqSException_Init) (void) {
  cMqSException = rb_define_class("MqSException", rb_eException);

  rb_define_method(cMqSException, "initialize", initialize, 3);

  rb_define_attr(cMqSException, "num", 1, 0);
  rb_define_attr(cMqSException, "code", 0, 0);
  rb_define_attr(cMqSException, "txt", 1, 0);

  id_new = rb_intern("new");
  id_num = rb_intern("@num");
  id_code = rb_intern("@code");
  id_txt = rb_intern("@txt");
}

mfg, Andreas Otto