From: "Berger, Daniel" <Daniel.Berger@...>
Date: 2005-07-26T04:18:37+09:00
Subject: Re: Ruby extensions on 64 bit linux

> -----Original Message-----
> From: Joe Van Dyk [mailto:joevandyk@gmail.com] 
> Sent: Monday, July 25, 2005 12:24 PM
> To: ruby-talk ML
> Subject: Ruby extensions on 64 bit linux
> 
> 
> http://www.ruby-talk.org/cgi-bin/scat.rb/ruby/ruby-talk/149446
>  makes me wonder, when writing C extensions, are there 
> anything I should be watching out for when intending the code 
> to be run on a 64 bit OS?
> 
> Thanks,
> Joe

* Don't assume a pointer and an int are the same size
* Don't make assumptions about the relative size of variable types
* Be wary of sign extension problems
* Use pointer arithmetic rather than address arithmetic
* Never cast malloc
* Explicitly include header files (-Wall will warn you about implicit
declarations)
* Watch out for data truncation, e.g. passing a size_t to something that
expects an int.
* Pack (align) your data structures as tightly as possible
* Watch out for data loss in constant expressions
* Use %p in your (s)printf's as appropriate
* Use #ifdef _LP64 as needed (or is that Solaris only?)

Regards,

Dan