c++ - Small logger class

Question

I am looking for a small lightweight logging system in c++. I have found some existing frameworks but I don't need all of their features at this point in time. I primarily am looking for a small system that can for example configure the log level output file. I am looking for an existing solution as I don't want to reinvent the wheel.

Answer 1

I strongly recommend this simple logging system: http://www.drdobbs.com/cpp/201804215. It is composed of a single header file. I have successfully used it on Linux, Windows and Mac OS X.

You write to the log like this:

FILE_LOG(logWARNING) << "Ops, variable x should be " << expectedX << "; is " << realX;

I really like the stream syntax. It is unobtrusive, typesafe and expressive. The logging framework automatically adds a at the end of the line, plus date, time and indentation.

Configuring the logs is pretty easy:

FILELog::ReportingLevel() = logDEBUG3;
FILE* log_fd = fopen( "mylogfile.txt", "w" );
Output2FILE::Stream() = log_fd;

This framework is also easy to extend. At work, we have recently made some adaptations to it so that it now uses an std::ofstream instead of a FILE*. As a result, we are now able to add nice features such as encrypting the logs, by chaining the streams.