Call of C function breaks memoty layout

[Andrey]

Hello,
I'm trying to bind C library for Tcl/Tk in D code. There is a 
function called "Tcl_CreateInterp()" which I declared as 
extent(C). When I call this function then layout of memory become 
broken - one of my global wstring variables loses it's value.
I don't know why it is happens. If I comment the call - I get 
normal execution.

May be somebody had faced with such problem. What to do?

My code:
> struct Tcl_Interp;
> extern (C)
>{
>    Tcl_Interp* Tcl_CreateInterp() nothrow;
>}