Variable Argument List Debug Log FIle

#include <iostream>
#include <string>
#include <cstdarg>  //for va_start
#include <windows.h> //for GetSystemTime, GetLocalTime
#include <fstream> //for std::wofstream
#include <sstream> //for sstream

std::wstring wformat_list(const wchar_t *fmt, ...)
{
    va_list va;
    va_start(va, fmt);

    //Returns the number of characters in the string referenced by a list of arguments.
    int len = _vscwprintf(fmt, va) + 1;  // _vscwprintf doesn't count terminating '\0'
    std::wstring str;
    str.resize(len);
    vswprintf_s(const_cast<wchar_t*>(str.c_str()), len, fmt, va);
    va_end(va);

    return str;
}

    //1. wformat_list test
    std::wcout << "1. wformat_list test" << std::endl;
    std::wstring testStr1 = wformat_list(L"MyTest %02d, %02d", 3, 8);
    std::wcout << testStr1 << std::endl << std::endl;

// GetSystemTime UTC 표준시간

std::wstring GetSystemTime()
{
    SYSTEMTIME st;

    GetSystemTime(&st);

    std::wstring str = wformat_list(L"%d-%02d-%02d %02d:%02d:%02d.%03d",
        st.wYear,
        st.wMonth,
        st.wDay,
        st.wHour,
        st.wMinute,
        st.wSecond,
        st.wMilliseconds);

    return str;
}

    //2. GetSystemTime test
    std::wcout << "2. GetSystemTime test" << std::endl;
    std::wstring testStr2 = GetSystemTime();
    std::wcout << testStr2 << std::endl << std::endl;

// GetLocalTime 컴퓨터의 시간

std::wstring GetLocalTime()
{
    SYSTEMTIME st;

    GetLocalTime(&st);

    /*
    std::wstring str = wformat_list(L"%d-%02d-%02d %02d:%02d:%02d.%03d",
        st.wYear,
        st.wMonth,
        st.wDay,
        st.wHour,
        st.wMinute,
        st.wSecond,
        st.wMilliseconds);
    */   

    std::wstring str = wformat_list(L"%d-%02d-%02d %02d:%02d:%02d",
        st.wYear,
        st.wMonth,
        st.wDay,
        st.wHour,
        st.wMinute,
        st.wSecond);

    return str;
}

    //3. GetLocalTime test
    std::wcout << "3. GetLocalTime test" << std::endl;
    std::wstring testStr3 = GetLocalTime();
    std::wcout << testStr3 << std::endl << std::endl;

void WriteTestLog()
{
    std::wofstream outFile(L"debugTest.log");
    if (outFile.is_open())
    {
        outFile << L"Test" << L"\n";
        outFile.close();
    }
}

    //4. Test Debug File
    std::wcout << "4. Save debugTest.log File" << std::endl;
    WriteTestLog();

#define MY_LOG(...)  wformat_list (__VA_ARGS__)

    //5. Variadic Macros Log test
    std::wcout << std::endl  << std::endl << "5. MY_LOG test" << std::endl;
    std::wstring testStr5 = MY_LOG(L"LOG %02d, %02d", 3, 8);
    std::wcout << testStr5 << std::endl << std::endl;

#define MY_DLOG(fmt, ...) DebugLog (__FUNCTIONW__, __LINE__, fmt, ##__VA_ARGS__)

void DebugLog(const wchar_t* funcName, int nLine, const wchar_t *fmt, ...)
{
    //variable argument string log
    va_list va;
    va_start(va, fmt);
    int len = _vscwprintf(fmt, va) + 1;  // _vscwprintf doesn't count terminating '\0'
    std::wstring str;
    str.resize(len);
    vswprintf_s(const_cast<wchar_t*>(str.c_str()), len, fmt, va);
    va_end(va);

    //format:     date:function_name(line)-log
    std::wstringstream stream;
    stream << GetLocalTime() << ":" << funcName << "(" << nLine << ")-" << str << L"\n";
    //std::wcout << stream.str();

    //save file
    std::wofstream outFile(L"debug.log", std::ios::app);
    if (outFile.is_open())
    {
        outFile << stream.str();
        outFile.close();
    }
}

    //6. Debug Line LOG
    std::wcout << "6. save debug.log File. " << std::endl;
    MY_DLOG(L"LOGFILE Test %02d, %02d", 3, 8);