An excruciatingly simple example to demonstrate that it's possible to write Ruby code in C.
First off you'll need the Ruby development header files, a C compiler, and a "make" utility... preferably the GNU toolchain.
The first of those you should get with the standard Ruby distribution. If you're using a packaged version for a Linux distro, you may have to search harder. When in doubt, compile Ruby from source.
Once you've accomplished that, we need to create a C function to wrap. In "function.h":
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#ifndef SAY_HELLO_H
#define SAY_HELLO_H void say_hello(); #endif |
And in "function.c":
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#include "function.h"
#include <stdio.h> void say_hello() { printf("Hello\n"); } |
Now, in "myfunc.c" we'll write our Ruby extension.
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#include "ruby.h"
#include "function.h" static VALUE wrapped_say_hello(VALUE self) { say_hello(); return self; } void Init_myfunc() { rb_define_method(rb_cObject, "say_hello", wrapped_say_hello, 0); } |
Now, the compilation isn't hard, but it's not exactly easy, either, so I need some way to create a makefile. Ruby comes to the aid.
In file "extconf.rb":
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require 'mkmf'
dir_config 'myfunc' create_makefile 'myfunc' |
And then we need only run:
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$ ruby extconf.rb && make |
Our Ruby extension is now happily sitting there as "myfunc.so".
Starting up IRB we can now:
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$ irb --simple-prompt
>> require 'myfunc' => true >> say_hello Hello => nil >>exit $ |
Questions?
