Re: Forward Declarations of types used in template container classes
On 4/8/2011 5:31 PM, Stephen Howe wrote:
Hi
I cant find whether this is valid C++, but I believe it is
// ---------------------------- start header file
#include<vector>
// Forward Declaration
class FooBar;
int SomeFunction1(FooBar); // Valid
declaration, I know this
int SomeFunction2(std::vector<FooBar>& ref); // But is this, on
using std::vector???
// ---------------------------- end header file
Yes FooBar is incomplete but all I am interested in is whether it is a
valid declaration.
All of this is to minimise header file dependency, so FooBar's
definition is not dragged in.
I know that where SomeFunction2 is defined, a full definition of
FooBar is needed.
Since in the context of the declaration of 'SomeFunction2' the full
definition of 'std::vector<FooBar>' is not required, it is not going to
be instantiated. If no instantiation happens, FooBar may be incomplete.
The declaration of 'SomFunction2' is legal, I suppose.
V
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