Simple C++ Logging - c++

Question

I have been set the task of:
To evolve a Logger class that can be integrated into your
projects/developments, most probably by declaring a single global instance; this will be used to capture and save log information.
There are 2 levels that are acceptable:
Logger - essentially just debug code in the
source, no class.
Logger - packaged in a class, with default behavior (not configurable). Controlled by _DEBUG and writes to std::clog (can be re-directed).
I really do not know where to start with this, and have spent hours trying to find help somewhere.

Answer 1

Your task may be to use a more complex Logger class which makes logging throughout your entire project easier due to functionalities such as
being able to break a string on multiple lines of code when debugging it
separate methods between error logging and debug logging
being able to turn logging on/off from that Logger instance, so that all the debug messages throughout your project become obsolete (instead of needing to comment all of them for instance)
adding other methods specific to your case (you will see below)
This is a Logger class I used for a windows project. It supports all the features previously mentioned. Feel free to use it.
#include "Logger.h"
Logger::Logger(
wstring wstrComponentName,
wstring wstrFunctionName) :
_wstrApplicationName(APPLICATION_NAME),
_wstrComponentName(StripFileName(wstrComponentName)),
_wstrFunctionName(wstrFunctionName)
{}
// This function doesn't support string, but wstring for it's arguments
VOID
Logger::Debug(
LPCWSTR format,
...
)
{
wstring wstrBase =
_wstrApplicationName + wstring(L": ") +
_wstrComponentName + wstring(L": ") +
_wstrFunctionName + wstring(L": ");
va_list args;
va_start(args, format);
wchar_t* msg = new wchar_t[_1kB];
wvsprintf(msg, format, args);
va_end(args);
wstring wstrOutput = wstrBase + msg;
delete[] msg;
OutputDebugString(wstrOutput.c_str());
}
// This function doesn't support string, but wstring for it's arguments
VOID
Logger::Error(
LPCWSTR format,
...
)
{
wstring wstrBase = wstring(L"[ERROR] ") +
_wstrApplicationName + wstring(L": ") +
_wstrComponentName + wstring(L": ") +
_wstrFunctionName + wstring(L": ");
va_list args;
va_start(args, format);
wchar_t* msg = new wchar_t[_1kB];
wvsprintf(msg, format, args);
va_end(args);
wstring wstrOutput = wstrBase + msg;
delete[] msg;
OutputDebugString(wstrOutput.c_str());
}
wstring
Logger::StripFileName(
__in wstring wstrFileName
)
{
DWORD dwLeftLimit = 0;
DWORD dwRightLimit = wstrFileName.length();
wstring wstrResult(L"FileName unavailable");
if (wstrFileName.rfind(L"\\") != wstring::npos)
{
dwLeftLimit = wstrFileName.rfind(L"\\") + 1;
}
if (wstrFileName.rfind(L".") != wstring::npos)
{
dwRightLimit = wstrFileName.rfind(L".");
}
if (dwRightLimit > dwLeftLimit)
{
wstrResult = wstrFileName.substr(
dwLeftLimit,
dwRightLimit - dwLeftLimit
);
}
return wstrResult;
}