Unexpected behaviour when using function as default argument

[anonymous23323124]

The following code works as expected:

template <class T> void fn(const T& arg = T()) { ... }

Defaulting the parameter to 0 when an fn<int> is called, for example.

However, I rewrote this code as follows:

template <class T> inline T Default() { return T(); }

template <class T> void fn(const T& arg = Default<T>()) { ... }

so that a particular argument type could have custom defaults if desired. However, when I use this code an integer argument now defaults to something like -8643563, i.e. it appears not to have been properly initialized.

My question, therefore, is what makes the second code sample not work, but the first to work?

Thanks for any help.

[anonymous23323124]

EDIT:

Explicitly putting the function as an argument:

fn(Default<int>());

works. It is only when the default argument is required:

fn();

that the argument is not set to default as expected.

[anonymous23323124]

EDIT EDIT: Ah fixed it now. I had implemented the relevant function (which was a template class member) outside the class and for some reason the compiler was ignoring the default arguments in the function prototype inside the class. To fix it I just put the default parameters in the header of the function definition outside the class.