Is typedef inside of a function body a bad programming practice?

Question

I have some class C and want to pass address of its instance and method to some functor in a test function Test_C_Foo1(). Functor is a template class

Answer 1

It's good. It's legal and localized.

Answer 2

IMHO, if the typedef is just to avoid typing or to make the pointer-to-member-function less cumbersome, as your example shows, thenit is fine.

But if the typedef reveals some particular concept, then it should be visible outside of the function.

A quick test to check it is the name of the typedef:

typedef int(C::*MEMFN1)(const std::string&); //OK: as local typedef, just an abbreviation

typedef int(C::*ACTION)(const std::string&); //Not so OK: Action is a new concept