From: nobu.nokada@...
Date: 2003-03-18T09:35:14+09:00
Subject: Re: ruby-dev summary 19773-19824

Hi,

At Tue, 18 Mar 2003 01:15:53 +0900,
Paul Brannan wrote:
> > [ruby-dev:19801] RSTRING(str)->ptr
> > 
> >   Nobu Nakada confirm that RSTRING(str)->ptr should be a NUL
> >   terminated string. However, it may be NULL in ruby-1.8.x.
> >   We must use StringValuePtr() to obtain non-NULL value.
> 
> Will rb_str2cstr be modified to use StringValuePtr(), or will extensions
> have to change to get non-NULL C-strings from STR2CSTR in 1.8.0?  If it
> is not modified, how should extension writers write code to work on both
> 1.6.x and 1.8.0?

Signatures of rb_str2cstr() and StringValuePtr() are different.
StringValuePtr() requires lvalue in order to get rid of
possibility of dangling pointer, so extensions should change to
use latter.

> I'm guessing rb_str2cstr will have to change, since
> strlen(RSTRING(str)->ptr) will break if RSTRING(str)->ptr is NULL.

If RSTRING(str)->ptr is NULL, RSTRING(str)->len is always 0.

> In what conditions will RSTRING(str)->ptr be NULL?

An example:

  ' '.dup.rstrip.gsub(/a/, '')

-- 
Nobu Nakada