> -----Original Message-----
> From: Robert Klemme [mailto:shortcutter / googlemail.com] 
> Sent: Monday, May 01, 2006 10:53 AM
> To: ruby-talk ML
> Subject: Re: Shortcut for [string].pack("p*").unpack("l").first ?
> 
> 
> 2006/5/1, Berger, Daniel <Daniel.Berger / qwest.com>:
> > Hi all,
> >
> > If I want to get the underlying pointer address of a
> > Ruby string, I can do this:
> 
> What do you want with a memory address in Ruby-land?  If 
> you're in an extension then there's probably an easier way to 
> get at the address.

Short answer: Win32API
 
strcmp1 = Win32API.new('msvcrt', 'strcmp', 'PP', 'I')
strcmp2 = Win32API.new('msvcrt', 'strcmp', 'LL', 'I')

str1 = "hello"
str2 = "hello"
str3 = "world"

addr1 = [str1].pack("p*").unpack("l").first
addr2 = [str2].pack("p*").unpack("l").first
addr3 = [str3].pack("p*").unpack("l").first

# Using strings
strcmp1.call(str1, str2) # 0
strcmp1.call(str1, str3) # -1

# Using string addresses
strcmp2.call(addr1, addr2) # 0
strcmp2.call(addr1, addr3) # -1

I suppose I could stop whining and just extend the String class. :)

class String
   def ptr
      [self].pack("p*").unpack("l").first
   end
end

This might be useful for Ruby/DL as well.

Regards,

Dan

PS - Many thanks to Heesob for teaching me some of these things lately.
:)


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