So, I want to get the console log to a file; that works fine, the problem lies when I tried to extend it to allow more inputs, and I don’t seem to know why.

Engine.h:

#pragma once

#ifdef ENGINE_EXPORTS
#define ENGINE_API __declspec(dllexport)
#else
#define ENGINE_API __declspec(dllimport)
#endif

// Logging functions
template <typename T, typename... Args>
ENGINE_API void EngineLog(const T& first, const Args&... args); // this started causing problems.

// Other unrelated functions

^ This is how I am handeling my header file.

In the Engine.cpp file; this is the function that does the logging:

//top of Engine:
#include "Engine.h"
template <typename T, typename... Args>
void EngineLog(const T& first, const Args&... args) {
    std::ostringstream oss;
    oss << first;
    ((oss << ' ' << args), ...);
    std::string strMessage = oss.str();
    std::cout << strMessage << std::endl;
    if (log_file.is_open()) {
        log_file << strMessage << std::endl;
    }
    else {
        std::cout << "Failed to log to file." << std::endl;
    }
}

I tried anything that came to mind when it came to fixing this, but I never managed to find why it wouldn’t compile, I hope this is obvious enough for anyone to help as this had me stumped for a while, and I would like to learn what I did wrong so I can never make the mistake again.

Maybe, there is a better way of doing dlls, but I am unaware of any other way…

Anyways; I Expect it to work in the Application project as follows:

EngineLog(38," <-- Numbers --> ", double, " ", integer);

Before I tried to expand it to accept arguments, it worked fine.

and I don’t know if it was something I tried to do, but I started getting errors in other functions in the Engine.h, about my “nested create directory” script accepting strings being invalid, but I can always just change that, that is unrelated to my current problem.