Re: [boost] Input archive loads seem to corrupt sharedcharacterstd::strings

From: Jens Seidel (jensseidel_at_[hidden])
Date: 2007-12-04 05:13:34

On Tue, Dec 04, 2007 at 04:59:17AM -0500, Hervé Brönnimann wrote:
> Inspection of the g++ string implementation (latest 4.1.x) shows that  
> resize() will *almost* always create a new rep and thus a new data()  
> for the string, if it is shared.  The only exception is when the  
> requested size == s.size().  Chuck, was this the bug that hit you?

To be honest, isn't a specific implementation not completely
unimportant? You don't want to rely on implementation details, right?
 
There is only one solution: remove the buggy casting code and replace it
with a proper one as suggested. Whether the proper one is slower or not
is unimportant!

> Seems to me, since you are going to rewrite your string anyway, you  
> might as well clear() it first, then resize(size).  That'll take care  
> of creating a new representation.  The problem with that is that it  
> will write over the string twice, first filling it with 0s then with  
> the read data.  But think about it:  if the string is shared, you  
> need to construct a new representation with the requested size  
> anyway, and it will have to be filled with 0s.

No, the problem is that this is implementation specific. Don't rely on
such stuff, rely on the C++ standard!
 
Jens