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comp.lang.ruby

Using gems from C extensions

Andre Nathan

1/30/2008 11:41:00 AM

Hello

I'm trying to use the json gem from a C extension. Doing this fails with
"no such file to load -- json (LoadError)":

rb_require("rubygems");
rb_require("json");

However, if I add

rb_funcall(rb_mKernel, rb_intern("gem"), 1, rb_str_new2("json"));

before rb_require("json"), then it works fine. Is that how it's supposed
to work?

Thanks,
Andre
4 Answers

Radoslaw Bulat

1/30/2008 8:33:00 PM

0

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Andre Nathan

1/30/2008 8:38:00 PM

0

On Thu, 2008-01-31 at 05:33 +0900, RadosÅ?aw BuÅ?at wrote:
> Maybe the better way is just use only rb_require("json") in C
> extension. Before loading extension, in ruby code user should manually
> do require "rubygems". I think it's better way because it doesn't
> assume that user has rubygems installed. In ruby1.9 there is no
> problem because rubygems is built-in into core.

This is for a controlled environment. I know I have rubygems :)

I just wanted to understand why the explicit call to "gem" is needed,
since in ruby code it isn't.

Best,
Andre

Eric Hodel

1/30/2008 11:14:00 PM

0

On Jan 30, 2008, at 03:40 AM, Andre Nathan wrote:
> I'm trying to use the json gem from a C extension. Doing this fails
> with
> "no such file to load -- json (LoadError)":
>
> rb_require("rubygems");
> rb_require("json");
>
> However, if I add
>
> rb_funcall(rb_mKernel, rb_intern("gem"), 1, rb_str_new2("json"));
>
> before rb_require("json"), then it works fine. Is that how it's
> supposed
> to work?

Yes. rb_require calls the base require, not the RubyGems overridden
one.

Instead of calling #gem, you can rb_funcall require instead.

Andre Nathan

1/31/2008 1:10:00 AM

0

On Thu, 2008-01-31 at 08:14 +0900, Eric Hodel wrote:
> Instead of calling #gem, you can rb_funcall require instead.

Strange, I tried that but it didn't find the json gem. I tried with both

rb_require("rubygems");
rb_funcall(rb_mKernel, rb_intern("require"), 1, rb_str_new2("json"));

and

rb_funcall(rb_mKernel, rb_intern("require"), 1,
rb_str_new2("rubygems"));
rb_funcall(rb_mKernel, rb_intern("require"), 1, rb_str_new2("json"));

I'm using ruby 1.8.6 (2007-09-23 patchlevel 110).

Andre