On Sun, Nov 23, 2003 at 03:08:42PM -0800, William Chops Westfield wrote:
> On Sunday, Nov 23, 2003, at 06:26 US/Pacific, Byron A Jeff wrote:
> >So here's the problem. The programming software is divided into a set
> >of low
> >level routines that twiddle the parallel port (vpp_on, bit_on, bit_off
> >and the
> >like), and the high level routines that read/program the chip using
> >the low
> >level routines. Since the low level routines are used by every
> >programming
> >algorithm, and are used for auto chip detection, we are trying to keep
> >these
> >in the main executable, only moving the high level routines to the
> >DLLs.
> >
> >The problem is how do you make callbacks into the main application's
> >low level
> >routines from the high level routines in the DLL?
>
> It sounds a bit backward to me - libraries generally contain the low
> level functions, rather than calling low-level functions in the main
> code.  So making the low level functions another library seems to make
> sense (a DLL is still a  library, right?)

Right.

>
> However, you COULD use pointers to functions...  sorta standard
> run-time linkage, I guess:

I was looking for a magic bullet that would auto link when the DLL was loaded

>
> in the DLL:
>
> static int (*v_vpp_on)(int) = uninitialized_vector_error;
> #define VPP_ON(i) (*(v_vpp_on)(i))
> static int (*v_bit_on)(int) = uninitialized_vector_error;
> #define BIT_ON(i) (*(v_bit_on)(i))
> static int (*v_bit_off)(int) = uninitialized_vector_error;
> #define BIT_OFF(i) (*(v_bit_off)(i))
>
> void initialize_vectors (int (*f_vpp)(int) f_vpp, int (*f_vpp)(int)
> f_on,
>                          int (*f_vpp)(int) f_off)
> {
>     v_vpp_on = f_vpp;
>     v_bit_on = f_on;
>     v_bit_off = f_off;
> }
>

I think I'll simply package the low level stuff into an autolinked DLL
so that the symbols are visible to the high level DLL when it is loaded.

BAJ

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