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Compiler Error C2970

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'class' : template parameter 'param' : 'arg' : an expression involving objects with internal linkage cannot be used as a non-type argument

You cannot use the name or address of a static variable as a template argument. The template class expects a const value that can be evaluated at compile time.

The following sample generates C2970:

// C2970.cpp
// compile with: /c
static int si;
// could declare nonstatic to resolve all errors
// int si;

template <int i>
class X {};

template <int *pi>
class Y {};

X<si> anX;   // C2970 cannot use static variable in templates

// this would also work
const int i = 10;
X<i> anX2;