Hey
The C standard does not require that a function pointer use the same
representation as any other type of pointer. In particular, on
processors with Harvard architectures, function pointers and regular
pointers are inherently different.
@Ian: do you have a reference section where this is described. I shortly
tried to search for a few keywords in the standard, but couldn't find
the obvious. I would just be interested in the details ...
@Steven: to give you a practical example: HP-UX on Itanium for example
uses two different representations for data pointers and functions
pointers: while data pointers are usual 64-bit addresses (purely
assuming 64-bit compilation mode), function pointers however are
pointers to a data structure called function description which contains
two further pointers: (a) the final target address and (b) a so-called
global data pointer for relative data addressing. Though if you would
print out a function pointer on HP-UX, you would also get a single
address, but it is NOT the address of the function to be called. This
example is not as good as Ian's one, but is somehow similar, I think.
Best regards,
Andi
