CODEWITHSUNDEEP
c++visual-studio-2010includeforward-declaration
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Reputation: 239

Are forward declarations needed after includes?

I have a class called GameState in its own file and that class has a pointer to another object of type StatusView which is in its own file. In GameState.h, I have included the StatusView header but when I try to compile it, I get the error:

missing type specifier - int assumed

However, when I forward declare StatusView even after including it, I am able to compile it. I have no clue what's causing the requirement to forward declare the class.

Upvotes: 2

Views: 140

Answers (1)

Potatoswatter
Potatoswatter

Reputation: 137800

You have a circular dependency between the headers. A includes B and B includes A, but B doesn't really include A because #pragma once was already evaluated for A. (It would be the same with a standard header guard.)

Because the inner inclusion is ignored, it's as if it were never there at all, and you need the forward declaration.

Upvotes: 6

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