# Embedded Ruby into C **URL:** \ **Category:** Ruby\ **Created:** [December 12, 2005, 3:18am UTC](https://www.ruby-forum.com/t/embedded-ruby-into-c/50011 "2005-12-12T03:18:19Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![joe-dumoulin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9dc877/32.png) [@joe-dumoulin](https://www.ruby-forum.com/u/joe-dumoulin)\ **Post date:** [December 12, 2005, 3:18am UTC](https://www.ruby-forum.com/t/embedded-ruby-into-c/50011/1 "2005-12-12T03:18:19Z")
Anyone got any good resources on embedding C into Ruby? The ones I found were a couple years old (i.e. for 1.6). What I’d like to do is be able to call Ruby functions from the C code (don’t care about return value here), and be able to call C functions (and get the return data) from the Ruby code. Thanks, Joe ---
**Author:** ![joe-dumoulin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9dc877/32.png) [@joe-dumoulin](https://www.ruby-forum.com/u/joe-dumoulin)\ **Post date:** [December 12, 2005, 3:57am UTC](https://www.ruby-forum.com/t/embedded-ruby-into-c/50011/2 "2005-12-12T03:57:21Z")
On 12/11/05, Joe Van D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Anyone got any good resources on embedding C into Ruby? The ones I > found were a couple years old (i.e. for 1.6). Chapter 21 in Programming Ruby, Second Edition covers it for Ruby 1.8. I haven’t tried it but it looks like a reasonably complete explanation. ---
**Author:** ![joe-dumoulin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9dc877/32.png) [@joe-dumoulin](https://www.ruby-forum.com/u/joe-dumoulin)\ **Post date:** [December 12, 2005, 4:06am UTC](https://www.ruby-forum.com/t/embedded-ruby-into-c/50011/3 "2005-12-12T04:06:21Z")
On 12/11/05, Joe Van D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Anyone got any good resources on embedding C into Ruby? The ones I > found were a couple years old (i.e. for 1.6). > > What I’d like to do is be able to call Ruby functions from the C code > (don’t care about return value here), and be able to call C functions > (and get the return data) from the Ruby code. I created a Ruby extension in C called ‘functions.so’. My ruby script is require’ing it. When I launch the Ruby script via ruby\_run() in C, I get ‘no such file to load – functions’ error. Any ideas? ---
**Author:** ![joe-dumoulin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9dc877/32.png) [@joe-dumoulin](https://www.ruby-forum.com/u/joe-dumoulin)\ **Post date:** [December 12, 2005, 4:12am UTC](https://www.ruby-forum.com/t/embedded-ruby-into-c/50011/4 "2005-12-12T04:12:22Z")
On 12/11/05, Joe Van D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > When I launch the Ruby script via ruby\_run() in C, I get ‘no such file > to load – functions’ error. The source code from the book is here: [http://www.pragmaticprogrammer.com/titles/ruby/code/index.html](http://www.pragmaticprogrammer.com/titles/ruby/code/index.html) The examples from “Extending Ruby” may help. ---
**Author:** ![joe-dumoulin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9dc877/32.png) [@joe-dumoulin](https://www.ruby-forum.com/u/joe-dumoulin)\ **Post date:** [December 12, 2005, 4:27am UTC](https://www.ruby-forum.com/t/embedded-ruby-into-c/50011/5 "2005-12-12T04:27:23Z")
On 12/11/05, Joe Van D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > When I launch the Ruby script via ruby\_run() in C, I get ‘no such file > to load – functions’ error. Aha, calling ruby\_init\_loadpath() did the trick. Essentially, I have a C program. I want to create a GUI (using ruby-gnome2) that can call the C program’s functions and process and report its data. Originally, I added a small UDP server to the C program that would listen for UDP messages from the Ruby GUI and that’s how they exchanged information. The process of creating all the message formats for the UDP messages was a pain in the butt though. So I’m thinking of a different approach (embedding a Ruby program in the C executable and create Ruby extensions for calling the C functions). Joe ---
**Author:** ![joe-dumoulin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9dc877/32.png) [@joe-dumoulin](https://www.ruby-forum.com/u/joe-dumoulin)\ **Post date:** [December 12, 2005, 4:30am UTC](https://www.ruby-forum.com/t/embedded-ruby-into-c/50011/6 "2005-12-12T04:30:23Z")
On 12/11/05, Joe Van D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > is require’ing it. > > Originally, I added a small UDP server to the C program that would > > listen for UDP messages from the Ruby GUI and that’s how they > > exchanged information. The process of creating all the message > > formats for the UDP messages was a pain in the butt though. So I’m > > thinking of a different approach (embedding a Ruby program in the C > > executable and create Ruby extensions for calling the C functions). Is this a reasonable approach: int main() { initialize ruby stuff create glib thread (or maybe pthread) { run ruby script that starts the GUI } } ---
**Author:** ![joe-dumoulin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9dc877/32.png) [@joe-dumoulin](https://www.ruby-forum.com/u/joe-dumoulin)\ **Post date:** [December 12, 2005, 6:03am UTC](https://www.ruby-forum.com/t/embedded-ruby-into-c/50011/7 "2005-12-12T06:03:42Z")
Anyone know how I can avoid the following compile errors? /usr/lib/libruby.so: undefined reference to `gnu_dev_major@GLIBC_2.3.3' /usr/lib/libruby.so: undefined reference to`gnu\_dev\_minor@GLIBC\_2.3.3’ ---
**Author:** ![joe-dumoulin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9dc877/32.png) [@joe-dumoulin](https://www.ruby-forum.com/u/joe-dumoulin)\ **Post date:** [December 12, 2005, 7:21am UTC](https://www.ruby-forum.com/t/embedded-ruby-into-c/50011/8 "2005-12-12T07:21:47Z")
One more question: Can I embed a Ruby extension into a C executable, run a Ruby script from the C executable, and have the Ruby script have access to the Ruby extension that’s in the C executable? ---
**Author:** ![joe-dumoulin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9dc877/32.png) [@joe-dumoulin](https://www.ruby-forum.com/u/joe-dumoulin)\ **Post date:** [December 12, 2005, 9:28am UTC](https://www.ruby-forum.com/t/embedded-ruby-into-c/50011/9 "2005-12-12T09:28:10Z")
Whew, figured it all out. My solution was to create a Ruby object in C that has access to all of the C program’s internal data, then create a normal Ruby object from a Ruby script file, then give that Ruby object the C/Ruby object that I first created. So, now, in C, I have this gigantic array of structs. Each struct has a bunch of fields and a bunch of ‘sub structs’ (i.e. pointers to other structs). What’s the easiest way to do reporting on this array of structs in Ruby? Thanks, Joe