[ILUG] EU Rejects Patent Software Law - For Now

[Bryan O'Donoghue]

Colm MacCarthaigh wrote:

> and then later call it with two "char *", the compiler will give it
> those types. I thought this was the best approach, as it's pretty
> flexible. The other approach is to use void pointers (which I don't like
> but that's for other reasons) and cast at every opportunity.  It works
> but it can unreliable. especially if you doing comparisons which use
> pointer-arithmetic. The third approach again is to have specific
> inline functions for each argument type, but that's exhaustive. And of 
> course the simplest approach is to use an argument-type agnostic
> pre-processsor macro - which I think you'll find is what I suggested :)
> 
> But my god is this getting obscure.


_ahem_ but,


#define compare_1(x,y) return(x!=y);


won't test memory location equivalence, rather variable value 
equivalence, thus typechecking is needed _forcing_ the calling 
entity/function to dref the input variables.


static inline compare_2(void * x, void *y){
	return (x!=y);
}

works for

int a;
int b;

if(compare_2(&a,&b))
	printf("Patent infringement\n");

whereas

if(compare_1(a,b))
	printf("Pay the bill\n");

won't, you see ?