C++ 写日志文件

//在指定文件路径写入指定信息，unicode版本
	void CLog::WriteLog(const wchar_t* filePath, const wchar_t* text)
	{
		//首先判断文件是否存在，如果不存在则创建，并在开头加入0xfeff;如果存在则直接写入
		if (_waccess(filePath, 0) == -1)
		{
			FILE* fp;
			_wfopen_s(&fp, filePath, L"wb");
			if (fp != NULL)
			{
				uint16_t wSignature = 0xFEFF;
				fwrite(&wSignature, 2, 1, fp);
				SYSTEMTIME st;
				GetLocalTime(&st);
				wchar_t buf[128] = { 0 };
				swprintf_s(buf, 128, L"%04d%02d%02d %02d:%02d:%02d:%03d	", st.wYear, st.wMonth, st.wDay, st.wHour, st.wMinute, st.wSecond, st.wMilliseconds);
				fwrite(buf, sizeof(wchar_t), wcslen(buf), fp);
				fwrite(text, sizeof(wchar_t), wcslen(text), fp);
				fwrite(L"\r\n", sizeof(wchar_t), 2, fp);
				fclose(fp);
			}
		}
		else 
		{
			FILE* fp;
			_wfopen_s(&fp, filePath, L"ab");
			if (fp != NULL)
			{
				SYSTEMTIME st;
				GetLocalTime(&st);
				wchar_t buf[128] = { 0 };
				swprintf_s(buf, 128, L"%04d%02d%02d %02d:%02d:%02d:%03d	", st.wYear, st.wMonth, st.wDay, st.wHour, st.wMinute, st.wSecond, st.wMilliseconds);
				fwrite(buf, sizeof(wchar_t), wcslen(buf), fp);
				fwrite(text, sizeof(wchar_t), wcslen(text), fp);
				fwrite(L"\r\n", sizeof(wchar_t), 2, fp);
				fclose(fp);
			}
		}
		
	}
	//在指定文件路径写入指定信息，ANSI版本
	void CLog::WriteLog(const char* filePath, const char* text)
	{
		FILE* fp;
		fopen_s(&fp, filePath, "a");
		if (fp != NULL)
		{
			SYSTEMTIME st;
			GetLocalTime(&st);
			char buf[128] = { 0 };
			sprintf_s(buf, 128, "%04d%02d%02d %02d:%02d:%02d:%03d ", st.wYear, st.wMonth, st.wDay, st.wHour, st.wMinute, st.wSecond, st.wMilliseconds);
			fwrite(buf, sizeof(char), strlen(buf), fp);
			fwrite(text, sizeof(char), strlen(text), fp);
			fwrite("\r\n", sizeof(char), 2, fp);
			fclose(fp);
		}
	}

	//在指定文件路径写入指定信息，格式化字符串版本
	void CLog::WriteLogEx(const char* filePath, const char* const format, ...)
	{
		std::string tmp;
		va_list maker = NULL;
		va_start(maker, format);
		size_t numofchar = _vscprintf(format, maker);
		if (numofchar > tmp.capacity())
		{
			tmp.resize(numofchar + 1);
		}
		vsprintf_s((char*)tmp.data(), tmp.capacity(), format, maker);
		va_end(maker);
		std::string text = tmp;

		FILE* fp;
		fopen_s(&fp, filePath, "a");
		if (fp != NULL)
		{
			SYSTEMTIME st;
			GetLocalTime(&st);
			char buf[128] = { 0 };
			sprintf_s(buf, 128, "%04d%02d%02d %02d:%02d:%02d:%03d ", st.wYear, st.wMonth, st.wDay, st.wHour, st.wMinute, st.wSecond, st.wMilliseconds);
			fwrite(buf, sizeof(char), strlen(buf), fp);
			fwrite(text.c_str(), sizeof(char), text.length(), fp);
			fwrite("\r\n", sizeof(char), 2, fp);
			fclose(fp);
		}
	}