🚀 go-pugleaf

In article <1992Nov2.193135.6803@cs.brown.edu> sdm@cs.brown.edu (Scott Meyers) writes:
>In article <1d1oirINN3vu@agate.berkeley.edu> jbuck@forney.berkeley.edu (Joe Buck) writes:
>| In article <1992Nov1.201547.4661@cs.brown.edu> sdm@cs.brown.edu (Scott Meyers) writes:
>| >Hence, given that this is legal,
>| > ..
>| >is there a good reason why this isn't?
>| >
>| >    void f(T*);
>| >    void (*pf)(void*) = f;
>| 
>| Certainly.  Consider the line that would be legal next:
>| 
>| T2* p;	// class T2 has no relation to class T
>| pf(p);
>| 
>| Now we have passed a pointer to T2 to a function that thinks it is getting
>| a pointer to T, and we have broken the type system.
>
>Boy, either I'm really dense or what we have here is a failure to
>communicate.  Clearly (I hope), if pf wants to do anything with its
                                   ^^^^^^^^^^^^^^^^^
>argument, it has to know what the real type is, i.e., it's going to have to
>do an explicit cast from void* to whatever the type really is.  Obviously
> ...

You _must_ have been day-dreaming a bit.
'pf' is only a pointer, not a function, so it cannot _do_ anything!
The argument is going to the function (i.e., 'f'), not to 'pf'.
'pf(p)' is only shorthand (and obviously often confusing such)
for '(pf*)(p)'.

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Markku Sakkinen (sakkinen@jytko.jyu.fi)
       SAKKINEN@FINJYU.bitnet (alternative network address)
Department of Computer Science and Information Systems
University of Jyvaskyla (a's with umlauts)
PL 35
SF-40351 Jyvaskyla (umlauts again)
Finland
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