Re: [Mingw-users] Mingw, COM, JNI, MFC and threads

[Jim S. <ni...@ab...>]

Jim Mason wrote:
> 
> Paul,
> 
>     In your recent remarks you suggested several compile
> options associated with the construction of DLLs in the
> context of JNI.  Among them:
> 
> >       a) verify that your mingw app is being compiled with -mthreads
> > (this provides a level of thread safety that doesn't exist when -
> > mthreads is not used)
> >
> >       b) verify that your mingw app also has the -fvtable-thunks
> > enabled (this is to insure that the COM stuff is being
> > initialized properly)
> >
> >       c) verify that you have -fnative-structs defined
> 
>     1. Do these options seem to you as reasonable defaults for the
>         construction of any DLL for use with java?

For simple JNI DLLs I haven't needed any of those options. 

> 
>     2. Put differently, is there any reason not to use these as
>         defaults for the construction of a JNI-implementing
>         DLL?

Yes.  See below.
> 
>     3. I certainly understand the implication of the
>         "-fnative-structs" option, but can you be a little more
>         specific about what is provided by "-mthreads" and
>         "-fvtable-thunks".  For example, if I used "-mthreads"
>         by default, am I simply giving up a little performance
>         for the sake of prudence, or is there rather more to
>         it?

I can't speak for -mthreads, but the '-fvtable-thunks' option isn't
JNI-related at all.  It is strictly a COM requirement. 

Jim S.