Ruby Language C Extensions Writing Inline C - RubyInLine
Example
RubyInline is a framework that lets you embed other languages inside your Ruby code. It defines the Module# inline method, which returns a builder object. You pass the builder a string containing code written in a language other than Ruby, and the builder transforms it into something that you can call from Ruby.
When given C or C++ code (the two languages supported in the default RubyInline install), the builder objects writes a small extension to disk, compiles it, and loads it. You don't have to deal with the compilation yourself, but you can see the generated code and compiled extensions in the .ruby_inline subdirectory of your home directory.
Embed C code right in your Ruby program:
- RubyInline (available as the rubyinline gem) create an extension automatically
RubyInline won't work from within irb
#!/usr/bin/ruby -w
# copy.rb
require 'rubygems'
require 'inline'
class Copier
inline do |builder|
builder.c <<END
void copy_file(const char *source, const char *dest)
{
FILE *source_f = fopen(source, "r");
if (!source_f)
{
rb_raise(rb_eIOError, "Could not open source : '%s'", source);
}
FILE *dest_f = fopen(dest, "w+");
if (!dest_f)
{
rb_raise(rb_eIOError, "Could not open destination : '%s'", dest);
}
char buffer[1024];
int nread = fread(buffer, 1, 1024, source_f);
while (nread > 0)
{
fwrite(buffer, 1, nread, dest_f);
nread = fread(buffer, 1, 1024, source_f);
}
}
END
end
end
C function copy_file now exists as an instance method of Copier:
open('source.txt', 'w') { |f| f << 'Some text.' }
Copier.new.copy_file('source.txt', 'dest.txt')
puts open('dest.txt') { |f| f.read }
