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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