Re: Pthread_join waits endlessly for already ended thread

[Ross Johnson <Ross.Johnson@homemail.com.au>]

Virgilio Alexandre Fornazin wrote:
> I had a problem similar to this, and creating an event handle for signaling
> solves nothing.
>
> I had this problem in plain win32 threads before. This always happened in
> DLL_PROCESS_DETACH. 
> It´s probably a bad design / limitation in win32 shared library model. The
> cause, if I remember, 
> is that the heap is locked in  some way that functions related to thread
> (TerminateThread if I'm 
> not missing other) must access this heap, then it deadlocks in some locking
> Windows have internally.
>   
This is good to know in case all else fails.

The library does have a compile-time condition that will cause threads 
to enter/exit via _beginthread()/_endthread() rather than the preferred 
_beginthreadex()/_endthreadex() versions, and MS documentation does say 
that _endthread() closes the Win32 thread handle resulting in no 
signalling, e.g. to WaitFor*(). This is one case that does exist in the 
library and needs to be fixed unless I'm mistaken.

The pre-built pthreads-win32 DLLs should be using _endthreadex() but in 
this case it is still the exiting thread that explicitly closes the 
Win32 thread handle before _endthreadex() is  called. I'd like to move 
that close to the joining thread.