[fluid-dev] Error in DllMain.

[Carlo Bramini]

Hello,
I had noticed that Fluidsynth for Windows is doing a very dangerous thing.
Actually, when I tried to run my test program with double click but 
incidentally nothing happened, I got quite immediately this suspect.
Into fluid_dll.c there is an implementation of DllMain with some code.
In this code, it creates an handle to a window to be used for setting the 
cooperative level in the directsound driver. This is wrong.
DllMain should never call some functions, because during the lock applied by 
the loader these functions may not be resolved, may not work correctly, could 
crash or can cause some strange behaviors. On Windows 9x/ME, this could even 
hang the entire OS. The NT kernel is more robust and protected, so the effects 
are tipically limited to the current local thread. It seems to me that it was 
implemented in a different manner in the past, because 
fluid_win32_create_window() is also called into fluid_dsound.c. Perhaps, 
somebody did this change without knowing the drawbacks, by thinking that in 
this way one window handle could be created just once, when the DLL is loaded, 
instead of creating and destroying it for each directsound object created.
More details could be found here:

https://msdn.microsoft.com/en-us/library/windows/desktop/dn633971(v=vs.85).aspx

I think that the best thing to do is to revert this change and restore original 
code, with the little addition of keeping the window handle private into each 
fluid_dsound_audio_driver_t structure.

Sincerely.