classes are instantiated despite explicit instantiations

[Raildex]

I have a header file vector4.h which contains the following:

#ifndef SRC_COMMON_VECTOR4_H
#define SRC_COMMON_VECTOR4_H
#include <glm/vec4.hpp>
#include <glm/gtc/quaternion.hpp>
namespace glm {
	extern template struct qua<float>;
	extern template struct vec<4, float, glm::defaultp>;
	extern template struct vec<4, long long, glm::defaultp>;
	extern template struct vec<4, long, glm::defaultp>;
	extern template struct vec<4, int, glm::defaultp>;
	extern template struct vec<4, unsigned long long, glm::defaultp>;
	extern template struct vec<4, unsigned long, glm::defaultp>;
	extern template struct vec<4, unsigned int, glm::defaultp>;
	extern template struct vec<4, short, glm::defaultp>;
	extern template struct vec<4, unsigned short, glm::defaultp>;
	extern template struct vec<4, signed char, glm::defaultp>;
	extern template struct vec<4, unsigned char, glm::defaultp>;
}
namespace raid {
	namespace math = ::glm;
	using quat = math::qua<float>;
	using float4 = math::vec<4, float, glm::defaultp>;
	using longlong4 = math::vec<4, long long, glm::defaultp>;
	using long4 = math::vec<4, long, glm::defaultp>;
	using int4 = math::vec<4, int, glm::defaultp>;
	using ulonglong4 = math::vec<4, unsigned long long, glm::defaultp>;
	using ulong4 = math::vec<4, unsigned long, glm::defaultp>;
	using uint4 = math::vec<4, unsigned int, glm::defaultp>;
	using short4 = math::vec<4, short, glm::defaultp>;
	using ushort4 = math::vec<4, unsigned short, glm::defaultp>;
	using byte4 = math::vec<4, signed char, glm::defaultp>;
	using ubyte4 = math::vec<4, unsigned char, glm::defaultp>;

} // namespace raid

#endif// SRC_COMMON_VECTOR4_H

I also have a corresponding vector4.cpp:

#include "common/vector4.h"
namespace glm {
	template struct qua<float>;
	template struct vec<4, float, glm::defaultp>;
	template struct vec<4, long long, glm::defaultp>;
	template struct vec<4, long, glm::defaultp>;
	template struct vec<4, int, glm::defaultp>;
	template struct vec<4, unsigned long long, glm::defaultp>;
	template struct vec<4, unsigned long, glm::defaultp>;
	template struct vec<4, unsigned int, glm::defaultp>;
	template struct vec<4, short, glm::defaultp>;
	template struct vec<4, unsigned short, glm::defaultp>;
	template struct vec<4, signed char, glm::defaultp>;
	template struct vec<4, unsigned char, glm::defaultp>;
}

However, the explicit instantiations do not seem to work (as I would expect them to).
Because whenever vector4.h gets included, glm automatically instantiates vec<4,T> in every combination.

I would expect my compiler to generate only one instantiation for the variations I specified in vector4.cpp.

main.cpp.json

Here is a trace of a file.

As you can see, the compiler (clang-cl in my case) instantiates all vector4's:

Is there a way to avoid this?

These are my glm compile defines:

GLM_FORCE_MESSAGES
GLM_FORCE_CXX98
GLM_FORCE_PURE
GLM_FORCE_LEFT_HANDED
GLM_FORCE_SWIZZLE
GLM_ENABLE_EXPERIMENTAL
GLM_FORCE_INLINE
GLM_FORCE_DEPTH_ZERO_TO_ONE

[ZXShady]

Hi, did you try instead defining GLM_EXTERNAL_TEMPLATE and including the proper header files instead.