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Compiler Error C2975

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'argument' : invalid template argument for 'type', expected compile-time constant expression

The template argument does not match the template declaration; a constant expression should appear within the angle brackets. Variables are not allowed as template actual arguments. Check the template definition to find the correct types.

Example

The following sample generates C2975 and also shows correct usage:

// C2975.cpp
template<int I>
class X {};

int main() {
   int i = 4, j = 2;
   X<i + j> x1;   // C2975
   X<6> x2;   // OK
}

C2975 also occurs when you use __LINE__ as a compile-time constant with /ZI. One solution would be to compile with /Zi instead of /ZI.

// C2975b.cpp
// compile with: /ZI
// processor: x86
template<long line>
void test(void) {}

int main() {
   test<__LINE__>();   // C2975
}