🚀 go-pugleaf

In article <1992Oct30.051334.1016@frumious.uucp>, pat@frumious.uucp (Patrick Smith) writes:
>    void f( int (*)(const char*, const char*) );
>    int g(const void*, const void*);
> 
>    f( g );     // Should this be allowed?
> 
> there might not be any semantic problems.
> 
> However, if the conversion from const char* to const void* involves
> any change to the actual representation of the pointer, then the
> compiler may need to generate a small function to use as the
> actual argument to f().  This function would just convert its
> parameters from const char* to const void* and then call g.

There is a problem with this if g is also a ponter to a function as the
compiler would be required to create such a stub function for invokation of
f() this would mean having function pointers into the *stack*.

    void f( int (*)(const char*, const char*) );
    
    void h(int (*g)(const void*, const void*)) {
      f( g );     // Should this be allowed?
    }

I suppose it's possible that a compiler could even have different
representations for `const char *' and `char *' but I don't think that
many compiler writers would start jumping up and down if you told them that
they couldn't.

By the way even if *all* data pointers had the same internal represention this
would not solve the problem as convertion from a pointer to multiply derived 
type, to a pointer to ones of it's base classes will unavoidably sometimes
require an adjustment.

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