On Wed, 2 Oct 2002 00:51:25 +0200, J.A. Magallon wrote:
>int (*pf)(data *);
>int f(data*);
>
>so you can:
>
>pf = f;
>pf(data).
>
>Fine. But what happens if:
>
>void (*pf)(data *);
>int f(data*);
>
>pf = f; // gcc happily swallows, gcc-3.2 gives a warning.
>pf(data).
Undefined Behaviour. I can easily imagine cases where, depending
on the calling convention and the actual return type, things could
go very very wrong. Consider struct returns...
This case, returning an int to a caller expecting void, is likely
to work on most normal machines -- the int would go into a GP result
register, and the GP result register is typically always part of the
caller-save set. The code is still utter crap, however.
>The (in)famous graphics driver all you know is doing this with the
>copy_info op for gart...
<censored>
/Mikael
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This archive was generated by hypermail 2b29 : Mon Oct 07 2002 - 22:00:33 EST