From: "Iñaki Baz Castillo" <ibc@...>
Date: 2011-02-07T11:32:17+09:00
Subject: rb_raise() causes segmentfault on xxxxx_alloc() function

Hi, my C extension uses rb_define_alloc_func(cResolver,
Resolver_alloc) to initialite the C library. If something goes wrong
in that initialization I want to raise an exception but using
rb_raise() within Resolver_alloc() produces a segmentfault.

The function is very easy:

-------------------------------------------------------------------
VALUE Resolver_alloc(VALUE klass)
{
  struct dns_ctx *dns_context;
  VALUE obj;

  if (dns_init(NULL, 0) < 0)
    rb_raise(rb_eStandardError, "udns dns_init failed");

  if (!(dns_context = dns_new(NULL)))
    rb_raise(rb_eStandardError, "udns dns_new failed");

  obj = Data_Wrap_Struct(klass, NULL, Resolver_free, dns_context);
  return obj;
}
-------------------------------------------------------------------


In order to force the error I change the dns_init line as follows:

  if (dns_init(NULL, 0) == 0)

and get a segmentfault. Is not allowed to raise an exception in the
alloc function of a class?

Thanks.


-- 
Iñaki Baz Castillo
<ibc@aliax.net>