Question

I’m reading a lot about “typedef functions”, but I getting casting errors when I try to call this one. What’s the correct syntax to call this function?

typedef ::com::Type* Func(const char* c, int i);

Answer 1

There’s no function in your code. There’s only a type name Func that stands for function type. There’s nothing to call there.

The name Func, as defined in your question, can be used in several different ways.

For example, you can use it to declare a function

Func foo;

The above is equivalent to declaring

::com::Type* foo(const char*, int);

This will also work for member function declarations. (However, you can’t use it to define a function).

For another example, you can use it when declaring a pointer to a function, by adding an explicit *

Func *ptr = &some_other_function;

The above is equivalent to declaring

::com::Type* (*ptr)(const char*, int) = &some_other_function;

For yet another example, you can use it as a parameter type in another function

void bar(Func foo)

in which case the function type will automatically decay to function pointer type, meaning that the above declaration of bar is equivalent to

void bar(Func *foo)

and equivalent to

void bar(::com::Type* (*foo)(const char*, int));

And so on.

In other words, show us what your are trying to do with it. As is your question is too broad to be answered specifically.