GHC 6.4.1 and Win32 DLLs: Bug in shutdownHaskell?

[Lennart Augustsson]

The memory allocated by the runtime system is never freed.
I've submitted a fix fir this.

	-- Lennart

Michael Marte wrote:
> Hello *,
> 
> before filing a bug report, I want others to comment on my problem. 
> Maybe it's my fault, not ghc's.
> 
> I wrapped up some Haskell modules in a Win32 DLL.
> Loading the DLL dynamically (with LoadLibrary) works fine. However, 
> whether I actually use the library or not, the program (an application 
> with MFC GUI) crashes upon termination.
> To find the reason for the crash, I added a new function for unloading 
> the DLL using FreeLibrary. FreeLibrary works fine, however the program 
> crashes when it returns to the main event loop. Interestingly, when I 
> reload the library (FreeLibrary followed by LoadLibrary) the program 
> continues working. However, every reload cycle causes the virtual size 
> of the process to increase by about 300K and the fourth reload fails 
> with the error message "getMBlock: VirtualAlloc failed with: 8" (appears 
> in a message window) accompanied by many repetitions of the message 
> "Timer proc: wait failed -- error code: 6" (appears on stderr) and 
> followed by the message "getMBlocks: misaligned block returned" (again 
> in a message window). Then the programm crashes.
> 
> Development takes place on Windows XP Professional using MS Visual 
> Studio 6.0 SP 5 and ghc 6.4.1. There are no references from the C++ side 
> to the Haskell heap. I build the DLL using the command
> 
> ghc --mk-dll -optdll--def -optdllFoo.def -o Foo.dll Foo.o Foo_stub.o 
> dllMain.c
> 
> dllMain.c looks as follows:
> 
> #include <windows.h>
> #include <Rts.h>
> 
> extern void __stginit_EUzu3820zu85(void);
> 
> static char* args[] = { "ghcDll", NULL };
>                       /* N.B. argv arrays must end with NULL */
> BOOL
> STDCALL
> DllMain(HANDLE hModule, DWORD reason, void* reserved) {
>    if (reason == DLL_PROCESS_ATTACH) {
>        /* By now, the RTS DLL should have been hoisted in, but we need 
> to start it up. */
>        startupHaskell(1, args, __stginit_Foo);
>        return TRUE;
>    } else if (reason == DLL_PROCESS_DETACH) {
>        shutdownHaskell();
>    }
>    return TRUE;
> }
> 
> I played around with hs_exit instead of shutdownHaskell, I moved 
> initialization and clean-up from DllMain to my library loader, nothing 
> helps. Even doing no clean-up whatsoever does not change the behaviour.
> 
> Any ideas?
> Michael
> 
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