--- In Boost-Users@y..., "bkarsjens" <karsjens+yahoo@v...> wrote:
The first thing I discovered when trying to get threads working is that the -mthreads option was not being used in jam. I added the following to the gcc-tools.jam file. I'm not totally sure it's right -- it's needed for mingw32, but I don't know if it is necessary for cygwin.
if $(NT) { flags gcc CFLAGS <threading>multi : -mthreads ; flags gcc LINKFLAGS <threading>multi : -mthreads ; }
Thanks. This may help me with the current problem we're having with gcc.
Adding that let's gdb actually work on it... It doesn't crash deep in the bowels of thread exiting in some kernel library routine. Although it still crashes in on_thread_exit doing handlers->push_front (func). Actually, it crashes in some STL stuff, but that's I'm not sure why, I'm not that good with gdb yet.
After digging through the implementation of threadmon.cpp, I realized that (unless I missed something) on_thread_exit was always called with the same argument, which is the address of cleanup in tss.cpp. Therefore all of the stuff in threadmon.cpp for keeping a list of functions registered with on_thread exit were not really needed, it would always have a list of the same pointer. So why not just keep that pointer and call it on thread exit. I also discovered that DllMain wasn't getting called at all because it wasn't defined as extern "C". This drastically simplifies threadmon.cpp:
on_thread_exit, even though it's an implementation detail, is a generalized concept that may be reused in the future. For instance, I'm considering a static thread::atexit() member. [snip code that changed threadmon to not use a list of registered functions]
Also, in tss.cpp, cleanup may be called without any handlers registered... I'm not sure if this was always the case, or if I introduced this case, so the cleanup function needs to do an if(handlers) check before actually trying to call them.
I don't quite follow this one, but I'll research it.
And now the tests pass! Wheee!
Great! I'll see if I can follow this message in order to get things working in CVS.
One more thing. I'm still not convinced for the need of the dll. The issue is needing to know when a thread has exited, and I think that could be done by an object that was destructed in a thread-proxy function. Since you are already using a thread_proxy function, I'm wondering if you considered this approach and if so, why you rejected it.
Because of the need for "thread adoption". Thread A is created outside of Boost.Threads. A callback is registered with Thread A that uses Boost.Thread's thread_specific_ptr<>. The memory allocated is never recovered since Thread A wasn't created by Boost.Threads and so isn't using the proxy. Bill Kempf