[plt-scheme] Xcode sample app

From: Matthew Flatt (mflatt at cs.utah.edu)
Date: Tue Mar 1 10:01:28 EST 2005

At Thu, 24 Feb 2005 15:03:17 -0800, Michael Larson wrote:
> Is there a sample OS X application that is linked to mzscheme? I built 
> the latest CVS and release builds but I am getting crashes just 
> creating a scheme env. [...]
> int main(int argc, char *argv[])
> {
>          Scheme_Env              *e = scheme_basic_env(); 
> <-------------------crashes in here

I think that MzScheme works with OS X only when scheme_set_stack_base()
is called with a non-zero second argument. I've never sorted this out
properly, but because MzScheme disables the Boehm GC's handling of
dynamic libraries, I think the GC also can't find static variables in
MzScheme code.

Calling scheme_set_stack_base() with a non-zero second argument obliges
the embedding application to register static variables that can contain
GCable pointers; use the scheme_set_stack_base() function or the
MZ_REGISTER_STATIC() macro. In my experience, explicitly registering
statics is better and more reliable than having the GC try to find
them. But if this is not practical for your application, we can
investigate more.


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