Ruby lnline question

ruby-talk
1

Dear all,

I'd like to have Ruby Inline create a Ruby method from the
following C code:

#include <stdio.h>

int main(int argc, char *argv[])
{
    int x;
    printf("%d\n",argc);
    for (x=0; x<argc; x++)
        printf("%s\n",argv[x]);
    return 0;
}

(so that I can enter a variable number of arguments and have these
returned.)

Now I tried:

#!/usr/local/bin/ruby -w

require 'rubygems'
require 'inline'

class Example
    inline(:C) do |builder|
    builder.c 'int main(int argc,char *argv[])
      {
        int x;
        printf("%d\n",argc);
        for (x=0; x<argc; x++)
          printf("%s\n",argv[x]);
        return 0;
      }'
  end
end

p Example.new.main(3,'a','b','c')

but got:

WARNING: 'char * argv[]' not understood
i.rb: In function ‘main’:
i.rb:15: error: ‘argv’ undeclared (first use in this function)
i.rb:15: error: (Each undeclared identifier is reported only once
i.rb:15: error: for each function it appears in.)
i.rb:9: warning: return type of ‘main’ is not ‘int’
/usr/local/lib/ruby/gems/1.8/gems/RubyInline-3.6.5/lib/inline.rb:402:in `build': error executing gcc -shared -fPIC -g -O2 -I /usr/local/lib/ruby/1.8/x86_64-linux -I /usr/local/include -o "/home/axel/.ruby_inline/Inline_Example_fad5.so" "/home/axel/.ruby_inline/Inline_Example_fad5.c" : 256 (CompilationError)
Renamed /home/axel/.ruby_inline/Inline_Example_fad5.c to /home/axel/.ruby_inline/Inline_Example_fad5.c.bad from /usr/local/lib/ruby/gems/1.8/gems/RubyInline-3.6.5/lib/inline.rb:679:in `inline'
  from i.rb:7

What am I missing ?

Thank you very much.

Best regards,

Axel

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2

Quoth Axel Etzold:

Dear all,

I'd like to have Ruby Inline create a Ruby method from the
following C code:

#include <stdio.h>

int main(int argc, char *argv)
{
    int x;
    printf("%d\n",argc);
    for (x=0; x<argc; x++)
        printf("%s\n",argv);
    return 0;
}

(so that I can enter a variable number of arguments and have these
returned.)

Now I tried:

#!/usr/local/bin/ruby -w

require 'rubygems'
require 'inline'

class Example
    inline(:C) do |builder|
    builder.c 'int main(int argc,char *argv)
      {
        int x;
        printf("%d\n",argc);
        for (x=0; x<argc; x++)
          printf("%s\n",argv);
        return 0;
      }'
  end
end

p Example.new.main(3,'a','b','c')

but got:

ERRORS! <snip>

What am I missing ?

Thank you very much.

Best regards,

Axel

This isn't how RubyInline is supposed to be used. RubyInline is mostly for
functions with a defined number of arguments AFAIK. It will infer the correct
ruby type <-> C type conversion automatically for you for that, but I don't
think it does varargs.

Furthermore, if you were writing a C ruby extension with a varargs function,
the signature is:

  VALUE func(int argc, VALUE *argv, VALUE obj)

(Where argc is the actual number of arguments, argv is the C array of the
arguments, and obj is the receiver (quoting README.EXT from Ruby source).)

HTH,

···

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