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?)

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

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;
}


BillW

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