From: "Iñaki Baz Castillo" <ibc@...>
Date: 2009-10-22T21:59:07+09:00
Subject: Re: Creating and raising custom exception in Ruby C extension

El Jueves, 22 de Octubre de 2009, Iñaki Baz Castillo escribió:
> El Jueves, 22 de Octubre de 2009, Iñaki Baz Castillo escribió:
> > Hi, I'm trying to create a CustomError exception in a Ruby C extension
> > and raise it:
> >
> >   VALUE class_standard_error = rb_const_get(rb_cObject,
> >  rb_intern("StandardError")); VALUE class_custom_error =
> >  rb_define_class_under(class_standard_error, "ClassError", rb_cObject);
> >  rb_raise(class_custom_error, "Oh, a custom error occurred !!!");
> >
> > Unfortunatelly when running it I get:
> >
> >   ArgumentError: wrong number of arguments(1 for 0)
> >     ./test_unit.rb:22:in `initialize'
> >     ./test_unit.rb:22:in `new'
> >     ./test_unit.rb:22:in `my_function'
> >     ./test_unit.rb:22:in `test_01
> >
> > Being "my_function" the Ruby method calling to the above C code.
> >
> > I suspect that the line:
> >   rb_raise(class_custom_error, "Oh, a custom error occurred !!!");
> > is not correct. How should look the first argument?
> 
> Let's try the following real code:
> 
> 	VALUE class_standard_error = rb_const_get(rb_cObject,
>  rb_intern("StandardError")); VALUE argv[0];
> 	VALUE new_error = rb_class_new_instance(0, argv, class_standard_error);
> 	rb_raise(new_error, "Oh an error ocurred !!!");
> 
> When calling the function containing it from Ruby I get:
> 
>   NoMethodError: undefined method `new' for #<StandardError: StandardError>
> 
> What am I doing wrong?

Definitively the line
   rb_raise(new_error, "Oh an error ocurred !!!");
is wrong. I think that "VALUE exception_object" (as the function requires as 
first argument) cannot be a class instance.

  API:
  rb_raise(VALUE exception_object, const char* format_string, ...)

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