[boost] Re: Re[2]: Re: [boost.thread] Static Library support for Windows

From: Michael Glassford (glassfordm_at_[hidden])
Date: 2004-08-05 11:56:40

"Roland" <roland.schwarz_at_[hidden]> wrote in message
news:20040805162509.ILOD9307.viefep19-int.chello.at_at_speedsnail...
> On Thu, 5 Aug 2004 18:10:10 +0200 (W. Europe Daylight Time) Roland
<roland.schwarz_at_[hidden]> wrote:
>
> > BTW.: while everything seems nice so far I just tried to use the
thing with
> > MFC. It turns out that the process / thread init / term need even
some more tweeking.
> > While every destructor is getting called properly the debug
version of MFC still
> > thinks it has discovered a memory leak. Since this will be able to
make a potential
> > user nervous, I am looking to a way to get rid of these messages
(by finding
> > the correct calling order).
>
> I am not anymore sure the leak has to do with the calling order. At
least I tracked
> the leak down to somewhere near:
>     // Intentional memory "leak"
>     // This is the only way to ensure the mutex in the global data
>     // structure is available when cleanup handlers are run, since
the
>     // execution order of cleanup handlers is unspecified on any
platform
>     // with regards to C++ destructor ordering rules.
> However I do not yet understand fully what is going on. What will I
need to
> expect beeing leaking?

What's being intentionally leaked?

1) The tls slot used by tss (not the same as the one used by
threadmon) is never released.
2) The tss_data_t struct allocated at the beginning of the
init_tss_data() function is also being leaked.

> I am not sure if there are additional leaks from
> elsewhere.
> Also, isn't the atexit well specified with respect to the global
dtors?

The cleanup handlers being referred to in the comment are tls cleanup
handlers. It has nothing to do with atexit:

1) The Windows cleanup handlers, when called by DllMain, (probably)
still have the same problem that they used to have tls_callback: they
can be called after constructors. I haven't gotten around to fixing
this yet.
2) IIUC, with the pthreads cleanup handlers, it is literally
unspecified whether they run before or after C++ destructors because
pthreads is a C-based standard.
3) I'm not sure how the MPThreads cleanup handlers work, but judging
by the comment it is also unspecified whether they run before or after
C++ destructors.

> Is this MS specific or is this in the standard?
>
> Could you please help me?

Hope that helps.

Mike