defining inline functions under template class definition
I'm trying to make an inline definition of a template class ctor under the class definition (I know you can do it inside, but I prefer to do it outside in the header file). However, MSVC is telling me that Matrix requires a template argument list in the ctor definition... I can easily solve this by defining the function inside the class (it still will be inlined), but I would prefer to do it outside due to esthetic reasons. Is there a way to solve this?
// .hpp
#pragma once
template <typename T, size_t rows, size_t cols>
class Matrix {
private:
constexpr size_t m_size = rows * cols;
std::array<T, m_size> m_arr;
public:
__forceinline Matrix();
};
Matrix::Matrix() : m_arr() { // this gives errors
// do ctor stuff
}
However, MSVC is telling me that Matrix requires a template argument list in the ctor definition...
Matrix::Matrix() : m_arr() { // this gives errors
You missed the template specification that should be given for the definition, that's probably what the compiler message tells you:
template <typename T, size_t rows, size_t cols> // <<<< This!
Matrix<T,rows,cols>::Matrix() : m_arr() {
// ^^^^^^^^^^^^^ ... and this
// do ctor stuff
}
... but I prefer to do it outside in the header file ...
To do so put the definition into a file that isn't atomatically picked up as a translation unit by your build system (eg some extension like .icc or .tcc ), and #include that one at the end of your header containing the template class declarations.
The complete code should look like
Matrix.hpp
#pragma once
#include <cstddef>
template <typename T, std::size_t rows, std::size_t cols>
class Matrix {
private:
constexpr static std::size_t m_size = rows * cols;
std::array<T, m_size> m_arr;
public:
__forceinline Matrix();
};
#include "Matrix.icc"
Matrix.icc
template <typename T, std::size_t rows, std::size_t cols>
Matrix<T,rows,cols>::Matrix() : m_arr() {
// do ctor stuff
}
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