(void *) to function pointer

[Henry Spencer]

In article <1037 at mwtech.UUCP> martin at mwtech.UUCP (Martin Weitzel) writes:
>A less portable solution to transfer a function pointer to a `void *'
>is an intermediate cast to an `int'. The ANSI standard allows such
>casts...

Yes and no.  The wording of the standard implies, but does not quite
state explicitly, that there is *some size* of integer that is big enough
to hold a pointer.  There is no promise that `int' suffices; it might
have to be `long', or even some nonstandardness like `long long'.

Note also that the standard does not promise that you can convert a
pointer to an integer (one that is big enough to hold it) and back
and get a useful pointer.  The description of pointer-integer conversions
is full of "implementation-defined" and "undefined" and makes very few
promises.
-- 
If the Space Shuttle was the answer,   | Henry Spencer at U of Toronto Zoology
what was the question?                 |  henry at zoo.toronto.edu   utzoo!henry