# Calling C functions from Embedded Ruby Interpreter **URL:** \ **Category:** ruby-talk\ **Created:** [24 April 2008 11:06 UTC](https://rubytalk.org/t/calling-c-functions-from-embedded-ruby-interpreter/46083 "2008-04-24T11:06:47Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Mohit\_Sindhwani1](https://avatars.discourse-cdn.com/v4/letter/m/dbc845/32.png) [@Mohit\_Sindhwani1](https://rubytalk.org/u/Mohit_Sindhwani1)\ **Post date:** [24 April 2008 11:06 UTC](https://rubytalk.org/t/calling-c-functions-from-embedded-ruby-interpreter/46083/1 "2008-04-24T11:06:47Z")
Hi Everyone, I know the subject line is quite a mouthful! Sorry about that. I've managed to embed a Ruby interpreter into my application and I can call Ruby functions from the code in my application. It works fine and returns results to me as expected. I can also ask it to run a script for me. Now, I'd like to get it to do some automation for me. My project starts up, loads a few things, sets a few properties, etc. I'd like to be able to automate this using the embedded interpreter. I expect the code in the script may be as simple as: set\_default\_color(0x00ff0000) set\_screen\_size(800,600) ...and so on. Now, as I understand it, in my application, I need to these C functions in it: VALUE set\_default\_color (VALUE color) VALUE set\_screen\_size (VALUE w, VALUE h) ... and so on. I just don't know what to do next! I'm not even sure what I should search for - should I like at how to create an extension? Does that mean that I need to get into the mkmf, etc. and compile some things for it to work (I shudder because my primary environment is Borland C++ Builder/ Turbo C++ and I had enough worries getting the interpreter to be compiled in). To use the script from the embedded interpreter, can I just ask it to run the script? I'm sorry if some of the questions/ explanations are a bit vague. Any help/ direction is greatly appreciated. Thanks Mohit. ---
**Author:** ![Mohit\_Sindhwani1](https://avatars.discourse-cdn.com/v4/letter/m/dbc845/32.png) [@Mohit\_Sindhwani1](https://rubytalk.org/u/Mohit_Sindhwani1)\ **Post date:** [24 April 2008 11:50 UTC](https://rubytalk.org/t/calling-c-functions-from-embedded-ruby-interpreter/46083/2 "2008-04-24T11:50:25Z")
Hello Again, I found that the example on this page: [http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/155482](http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/155482) does have the necessary to help me connect the dots. I was staring at the example for quite a while before I sent the email out, but I guess I just didn't see it. Thanks anyway. Cheers, Mohit. 4/24/2008 | 7:48 PM. Mohit Sindhwani wrote: > **···** > > > Hi Everyone, > > > > I know the subject line is quite a mouthful! Sorry about that. > > > > I've managed to embed a Ruby interpreter into my application and I can call Ruby functions from the code in my application. It works fine and returns results to me as expected. I can also ask it to run a script for me. > > > > Now, I'd like to get it to do some automation for me. My project starts up, loads a few things, sets a few properties, etc. I'd like to be able to automate this using the embedded interpreter. I expect the code in the script may be as simple as: > > set\_default\_color(0x00ff0000) > > set\_screen\_size(800,600) > > ...and so on. > > > > Now, as I understand it, in my application, I need to these C functions in it: > > VALUE set\_default\_color (VALUE color) > > VALUE set\_screen\_size (VALUE w, VALUE h) > > ... and so on. > > > > I just don't know what to do next! I'm not even sure what I should search for - should I like at how to create an extension? Does that mean that I need to get into the mkmf, etc. and compile some things for it to work (I shudder because my primary environment is Borland C++ Builder/ Turbo C++ and I had enough worries getting the interpreter to be compiled in). > > > > To use the script from the embedded interpreter, can I just ask it to run the script? > > > > I'm sorry if some of the questions/ explanations are a bit vague. Any help/ direction is greatly appreciated. > > > > Thanks > > Mohit. ---
**Author:** ![Simon\_Krahnke](https://avatars.discourse-cdn.com/v4/letter/s/b782af/32.png) [@Simon\_Krahnke](https://rubytalk.org/u/Simon_Krahnke)\ **Post date:** [24 April 2008 12:35 UTC](https://rubytalk.org/t/calling-c-functions-from-embedded-ruby-interpreter/46083/3 "2008-04-24T12:35:04Z")
\* Mohit Sindhwani \ (13:06) schrieb: > I know the subject line is quite a mouthful! Sorry about that. I don't see anything wrong in the subject line. > I've managed to embed a Ruby interpreter into my application and I can > call Ruby functions from the code in my application. It works fine and > returns results to me as expected. I can also ask it to run a script > for me. Grats. > set\_default\_color(0x00ff0000) > set\_screen\_size(800,600) > ..and so on. > > Now, as I understand it, in my application, I need to these C functions > in it: > VALUE set\_default\_color (VALUE color) > VALUE set\_screen\_size (VALUE w, VALUE h) > .. and so on. > > I just don't know what to do next! Well, the Pickaxe has a chapter on this stuff. Try rb\_define\_global\_function("set\_default\_color", &set\_default\_color, 1) There also is rb\_define\_module\_function(VALUE model, char \*name, VALUE(\*func)(), int argc) and rb\_define\_singleton\_method taking the same arguments. I never tried any of these, and don't quit know how to tell a module function from a singleton function from a system function. (The last one is in Kernel, the other two can be in any module or class.) mfg, simon .... l ---
**Author:** ![Mohit\_Sindhwani1](https://avatars.discourse-cdn.com/v4/letter/m/dbc845/32.png) [@Mohit\_Sindhwani1](https://rubytalk.org/u/Mohit_Sindhwani1)\ **Post date:** [27 April 2008 12:06 UTC](https://rubytalk.org/t/calling-c-functions-from-embedded-ruby-interpreter/46083/4 "2008-04-27T12:06:24Z")
Hi Simon First, my apologies on the late response. Thanks for your email relating to my request. Simon Krahnke wrote: > \* Mohit Sindhwani \ (13:06) schrieb > > > I know the subject line is quite a mouthful! Sorry about that. > >      > > I don't see anything wrong in the subject line. > >    Haha, thanks for that! > > I've managed to embed a Ruby interpreter into my application and I can call Ruby functions from the code in my application. It works fine and returns results to me as expected. I can also ask it to run a script for me. > >      > > Grats. > > > set\_default\_color(0x00ff0000) > > set\_screen\_size(800,600) > > ..and so on. > > > > Now, as I understand it, in my application, I need to these C functions in it: > > VALUE set\_default\_color (VALUE color) > > VALUE set\_screen\_size (VALUE w, VALUE h) > > .. and so on. > > > > I just don't know what to do next! > >      > > Well, the Pickaxe has a chapter on this stuff. > > Try > > rb\_define\_global\_function("set\_default\_color", &set\_default\_color, 1) > > There also is rb\_define\_module\_function(VALUE model, char \*name, > VALUE(\*func)(), int argc) and rb\_define\_singleton\_method taking the same > arguments. I never tried any of these, and don't quit know how to tell a > module function from a singleton function from a system function. (The > last one is in Kernel, the other two can be in any module or class.) Ya, actually wisdom strikes soon after one requests for help. I did find the necessary stuff in one of the links that I had been staring at for a while... and after that, it was easy enough to connect up the dots to get things moving. Thanks for the example. I followed the procedure for defining a module and then creating the functions within it. Not sure if I eventually want it to be that way but I know enough now to keep exploring. > mfg, simon .... l >    > Might I ask what "mfg" stands for? Thanks again. Cheers, Mohit. 4/27/2008 | 7:53 PM. ---
**Author:** ![David\_A\_Black1](https://avatars.discourse-cdn.com/v4/letter/d/bcef8e/32.png) [@David\_A\_Black1](https://rubytalk.org/u/David_A_Black1)\ **Post date:** [27 April 2008 12:29 UTC](https://rubytalk.org/t/calling-c-functions-from-embedded-ruby-interpreter/46083/5 "2008-04-27T12:29:51Z")
Hi -- > **···** > > On Sun, 27 Apr 2008, Mohit Sindhwani wrote: > > > Hi Simon > > > > First, my apologies on the late response. Thanks for your email relating to my request. > > > > Simon Krahnke wrote: > > > > > \* Mohit Sindhwani \ (13:06) schrieb > > > > > > > I know the subject line is quite a mouthful! Sorry about that. > > > > > > I don't see anything wrong in the subject line. > > > > Haha, thanks for that! > > > > > > I've managed to embed a Ruby interpreter into my application and I can call Ruby functions from the code in my application. It works fine and returns results to me as expected. I can also ask it to run a script for me. > > > > > > Grats. > > > > > > > set\_default\_color(0x00ff0000) > > > > set\_screen\_size(800,600) > > > > ..and so on. > > > > > > > > Now, as I understand it, in my application, I need to these C functions in it: > > > > VALUE set\_default\_color (VALUE color) > > > > VALUE set\_screen\_size (VALUE w, VALUE h) > > > > .. and so on. > > > > > > > > I just don't know what to do next! > > > > > > Well, the Pickaxe has a chapter on this stuff. > > > > > > Try > > > > > > rb\_define\_global\_function("set\_default\_color", &set\_default\_color, 1) > > > > > > There also is rb\_define\_module\_function(VALUE model, char \*name, > > > VALUE(\*func)(), int argc) and rb\_define\_singleton\_method taking the same > > > arguments. I never tried any of these, and don't quit know how to tell a > > > module function from a singleton function from a system function. (The > > > last one is in Kernel, the other two can be in any module or class.) > > > > Ya, actually wisdom strikes soon after one requests for help. I did find the necessary stuff in one of the links that I had been staring at for a while... and after that, it was easy enough to connect up the dots to get things moving. > > > > Thanks for the example. I followed the procedure for defining a module and then creating the functions within it. Not sure if I eventually want it to be that way but I know enough now to keep exploring. > > > > > mfg, simon .... l > > > > Might I ask what "mfg" stands for? > > Mit freundlichen Grüßen (with friendly greetings -- more or less like > "Best wishes"). > > David > > -- > Rails training from David A. Black and Ruby Power and Light: >    INTRO TO RAILS June 9-12 Berlin >    ADVANCING WITH RAILS June 16-19 Berlin >    INTRO TO RAILS June 24-27 London (Skills Matter) > See [http://www.rubypal.com](http://www.rubypal.com) for details and updates! ---
**Author:** ![Mohit\_Sindhwani1](https://avatars.discourse-cdn.com/v4/letter/m/dbc845/32.png) [@Mohit\_Sindhwani1](https://rubytalk.org/u/Mohit_Sindhwani1)\ **Post date:** [27 April 2008 12:33 UTC](https://rubytalk.org/t/calling-c-functions-from-embedded-ruby-interpreter/46083/6 "2008-04-27T12:33:41Z")
David A. Black wrote: > Hi -- > > > > mfg, simon .... l > > > > Might I ask what "mfg" stands for? > > Mit freundlichen Grüßen (with friendly greetings -- more or less like > "Best wishes"). > > David Thanks David! That's why I love this list - you learn a little bit about languages all the time 🙂 Cheers, Mohit. 4/27/2008 | 8:32 PM. ---
**Author:** ![Pascal\_Bourguignon1](https://avatars.discourse-cdn.com/v4/letter/p/b5ac83/32.png) [@Pascal\_Bourguignon1](https://rubytalk.org/u/Pascal_Bourguignon1)\ **Post date:** [27 April 2008 12:40 UTC](https://rubytalk.org/t/calling-c-functions-from-embedded-ruby-interpreter/46083/7 "2008-04-27T12:40:07Z")
Mohit Sindhwani \ writes: > David A. Black wrote: > > > Hi -- > > > > > > mfg, simon .... l > > > > > > Might I ask what "mfg" stands for? > > > > Mit freundlichen Grüßen (with friendly greetings -- more or less like > > "Best wishes"). > > > > David > > Thanks David! That's why I love this list - you learn a little bit > about languages all the time 🙂 Also, you could improve you google-fu. You'd find nice tools such as: [http://www.silmaril.ie/cgi-bin/uncgi/acronyms?MFG](http://www.silmaril.ie/cgi-bin/uncgi/acronyms?MFG) > **···** > > -- > \_\_Pascal Bourguignon\_\_ > > > **[Free Software by Pascal Bourguignon](http://informatimago.free.fr/i/)** > > > > Pascal Bourguignon's Software ---
**Author:** ![Mohit\_Sindhwani1](https://avatars.discourse-cdn.com/v4/letter/m/dbc845/32.png) [@Mohit\_Sindhwani1](https://rubytalk.org/u/Mohit_Sindhwani1)\ **Post date:** [27 April 2008 12:45 UTC](https://rubytalk.org/t/calling-c-functions-from-embedded-ruby-interpreter/46083/8 "2008-04-27T12:45:20Z")
Pascal Bourguignon wrote: > Also, you could improve you google-fu. You'd find nice tools such as: > [http://www.silmaril.ie/cgi-bin/uncgi/acronyms?MFG](http://www.silmaril.ie/cgi-bin/uncgi/acronyms?MFG) Point taken, Pascal. Sorry about that. It was just a friendly question piggy-backed to my response to the original reply. But, I understand what you mean. I could have avoided the responses that followed. By the way, thanks for the link - it's quite neat! Mfg, Mohit. ---
**Author:** ![Arlen\_Christian\_Mar1](https://avatars.discourse-cdn.com/v4/letter/a/9de053/32.png) [@Arlen\_Christian\_Mar1](https://rubytalk.org/u/Arlen_Christian_Mar1)\ **Post date:** [27 April 2008 12:58 UTC](https://rubytalk.org/t/calling-c-functions-from-embedded-ruby-interpreter/46083/9 "2008-04-27T12:58:14Z")
Hi, > **···** > > On Sun, Apr 27, 2008 at 10:40 PM, Pascal Bourguignon \ wrote: > > > Also, you could improve you google-fu. You'd find nice tools such as: > > [http://www.silmaril.ie/cgi-bin/uncgi/acronyms?MFG](http://www.silmaril.ie/cgi-bin/uncgi/acronyms?MFG) > > Hmm, I tried something similar, but I suppose the German answer was one I > skipped over subconsciously. We all learn something new! > > Cheers, > Arlen.