>> The interesting part is that it doesn't leak if use the version of threads
>> built using the CRT as a .dll rather than static link. I also believe that
>> the actual culprit is somewhere in boost.function since the code for
>> boost.thread is so straight forward.

>This sounds more like a mismatch between the runtime libraries that
>Boost was compiled for (MSVCRT.DLL I'm pretty sure) and the one you're
>linking with. Do you get a linker error indicating that there are
>conflicting libraries?

Hmmm no linker errors or warnings. I've set my main exe to statically link. if i use the version of threads that statically links to msvcrt71 or dynamically to msvcrt71.dll it doesn't seem to make any difference. Our boost libraries where compiled here for msvcrt71 and i can confirm this.

As i say if my main exe uses msvcrt71.dll then theres no leak.