"Rune Torgersen" wrote in message:
> I have a piece of code that worked perfectly under GCC 3.3.3, but fails
> to even compile under GCC 3.4.3
>
>
#include <iostream>
> class testfnptr
> {
> public:
> bool (testfnptr::*func)(void);
>
> testfnptr() {func = 0; };
>
> bool dotest()
> {
std::cout << "func = " << func << '\n';
> if (0 != (this->*func))
You say you want to check if the member function pointer 'func' is NULL... so this test should be simply:
if (0 != func)
i.e. you don't want to de-reference the pointer, since you are not calling any function (it wouldn't make sense - there
is no function to call ;-))
> {
> (this->*func)();
> }
> }
BTW, this function should return a value.
> };
>
> int main()
> {
> testfnptr testing;
> testing.dotest();
>
> return 0;
> }
>
> What I'm trying to do is to check if a member-function pointer is NULL
> before I call the function. (In my real application I have a function
> table that I go through, and some entries are set to NULL)
>
> GCC 3.4 3 says:
> testfnptr.cpp: In member function `bool testfnptr::dotest()':
> testfnptr.cpp:11: error: invalid use of non-static member function
>
> I have tried to check func directly, but that variable always have a
> value != 0.
Not on my system (GCC 3.4.3 also)... output is:
func = 0
I'm not entirely convinced the entire exercise is valid, however (I'm not sure what the C++ standard has to say about
permissible values for pointers to member functions). Perhaps safer would be to set a (member) flag to indicate whether
your member function pointer has been set to something sensible.
HTH,
--
Lionel B
