From: sh@...
Date: 2009-05-05T23:06:09+09:00
Subject: [ruby-core:23359] Re: Ruby/DL Documentation

Hi,

It is helpful to read test/dl/test_*.rb in ruby-1.9.tar.gz.
You have to master pack and unpack anyway.
The following is an example.

$ cat sum.c
double sum(double *arry, int len)
{
  double ret = 0;
  int i;
  for(i = 0; i < len; i++){
    ret = ret + arry[i];
  }
  return ret;
}

$ gcc -shared sum.c -o libsum.so

$ cat d.rb
require 'dl/import'
module M
  extend DL::Importer
  dlload './libsum.so'
  extern 'double sum(double*, int)'
end
p M.sum([2.0, 3.0, 4.0].pack("d*"), 3)

$ ruby-1.9 -v d.rb
ruby 1.9.2dev (2009-05-02 trunk 23326) [i686-linux]
9.0


2009/5/4 Aston <blackapache512-ticket@yahoo.com>:
> Hello,
>
> recently i have been trying to learn and use dl library. while searching i
> found this excellent link
> http://www.jbrowse.com/text/rdl_en.html
>
> unfortunately it is specific to 1.8.x
>
> i wonder how people here use DL, since it is very scarcely documented. i
> have been trying to
> hack around ./ext/dl/*.c files but i have gained very little usable
> information.
>
> ok, my question is about passing an array from ruby to some native libraries
> (IPP(http://software.intel.com/en-us/intel-ipp/) to be specific)
> on windows. yes i about other alternatives, i could embed ruby in my app and
> do whatever, there is gr8 support there
> but this is about quickly loading and using native libraries via dynamic
> loader.
>
> consider code below
> some_fast_math_function( float* array, int len);
>
> then how to pass 'array' argument from ruby ?
> i tried this
>
> require 'dl'
>
> module NativeLibs
> # do the job for accessing some_fast_math_function
> end
>
> array = DL.malloc(size)
> NativeLibs.some_fast_math_function( array, size) # crashes :(
>
> some how sucess is elusive for me, this crashes(core dumps) for me, i am
> sure this is due to my inexperienced stunts with DL
>
> Aston
>
>
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