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List:       ruby-talk
Subject:    [ruby-talk:00150] Re: calling a Ruby function from C?
From:       shugo () aianet ! ne ! jp (Shugo Maeda)
Date:       1998-12-27 14:51:30
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Hi, Bryce,

In message "[ruby-talk:00146] calling a Ruby function from C?"
"Bryce" <crowdog@siscom.net> wrote:

|What I am wanting to accomplish is like a callback.
|
|I would like to send my C code a Ruby function pointer
|so that C can call my Ruby function.

You can use a Method object to pass a Ruby function to C function.

C:

	VALUE c_func(VALUE self, VALUE func)
	{
	    ...
	    rb_funcall(func, rb_intern("call"), 0);
	    ...
	}

Ruby:

	def foo
	  puts "foo"
	end

	c_func(method(:foo))

And you can also pass a Proc object to c_func.

	p = proc { puts "foo" }
	c_func(p)


But it may be better way to define an iterator.
-- The name `iterator' may be obsolete.

C:

	VALUE c_func2(VALUE self)
	{
	    ...
	    rb_yield(Qnil);
	    ...
	}

Ruby:

	def foo
	  puts "foo"
	end

	c_func2 { foo }

You can also pass a method object to c_func2:-)
like this:

	c_func(&method(:foo))

& means passing an argument as an iterator block.

Hope this helps, Salut!
Shugo

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