Re: [Boost-users] shared_ptr leaking memory and crashing / gcc 3.4.6

Subject: Re: [Boost-users] shared_ptr leaking memory and crashing / gcc 3.4.6
From: Michael (boost_at_[hidden])
Date: 2008-10-29 07:35:58

Anybody interested in this or could point me to a different boost list?

Michael wrote:
> Hello,
> 
> I figured that shared_ptr (boost 3.4, but I don't think this is really a 
> boost problem) will lose memory in the following example
> 
> #include <boost/shared_ptr.hpp>
> 
> struct X
> {
>   int y;
> };
> typedef boost::shared_ptr<X> XRef;
> 
> XRef getx()
> {
>   throw 0;
> }
> 
> 
> int main(int argc, char** argv)
> {
>   while (true)
>   {
>     XRef myX;
>     try
>     {
>       myX = getx();
>     }
>     catch(...)
>     {
>     }
>   }
> }
> 
> Compile: g++ -I/usr/local/include test.C -o test
> 
> On every iteration of the while loop it loses memory and after approx. 1 
> million iterations it dies with signal 10 or 11.
> 
> Changing that pattern to
>   try
>   {
>     XRef y = getx();
>     myX = y;
>   }
>   catch(...)
>   {
>   }
> 
> fixes the problem (I assume in that case it will call shared_ptrs copy 
> constructor instead of its assignment operator).
> 
> Platform is FreeBSD 6, gcc 3.4.6. It only happens when compiled like 
> above (without optimization). On optimization levels 2 and above (-O2) 
> it works ok. Maybe somebody using gcc 3.4 can check if this also happens 
> on other platforms. gcc 4 works ok without any issues, so I assume this 
> is a compiler problem. It might still be a good idea to put a warning in 
> the documentation about this.
> 
> cheers
> Michael
> 
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