On Mon, 3 Feb 2020 at 07:21, aotto <aotto1968@xxxxxxxxxxx> wrote:
>
> Hi, the following scenario has a "definition hole" in the "C" language
>
> code example:
>
> -------------------------
> struct base {
> ...
> };
>
> struct A {
> struct base obj;
> ...
> } aObj;
>
> struct B {
> struct base obj;
> ...
> } bObj;
>
> void method_base (struct base * hdl, ...);
>
> method_base(&aObj, ...)
> method_base(&bObj, ...)
> ------------------------
>
> - a POINTER to "A" is also a valid POINTER to "base"
>
> - a POINTER to "B" is also a valid POINTER to "base"
>
> - a POINTER to "base" is NOT a valid POINTER to "A" and "B"
>
> I require a solution for this problem WITHOUT forced pointer cast
> code and without "void* and type-check" inflation.
>
> The following solutions are acceptable:
>
> 1. "gcc" discover by its own that "base" is a "friend" of "A" and "B".
I hate this idea, but I hate the use of the word "friend" even more.
Please pick a name that doesn't mean something different in C++
already.
> 2. add a "frienddef" keyword like "typedef" using:
> typedef struct base * baseP;
> typedef struct A * aP;
> typedef struct P * bP;
> frienddef baseP aP;
> frienddef baseP bP;
> 3. add a #PRAGMA to enable/disable this feature
> 4. add a "gcc" api to easy extend "GCC" without being FORCED
> to "hack" the core.
>
> thanks for your help
>
