I've had a closer look at this

On Windows, the error names and numbers are different:
https://msdn.microsoft.com/en-us/library/windows/desktop/ms740668%28v=vs.85%29.aspx

What I'd like to see in Errdes.hxx:

• some classes:
  • a base class called AbstractError
  • a subclass of AbstractError called NumericError
  • three subclasses of NumericError called ErrnoError, OpenSSLError and X509Error
• each class should override the << stream operator to return a string for use in log messages
• each class should provide a static factory method for getting an instance, e.g.
  const ErrnoError& ErrnoError::getErrorInstance(const int errorCode);
• instances should be cached, the getErrorInstance method should always return the same instance for a given error code
• make sure you don't assume the numeric values that the names correspond to, you must make sure you use each macro somewhere. E.g. if you were putting them in a hash map at initialization time, you might do:
  my_map[ENOENT] = ErrnoError(ENOENT, "ENOENT", "No such file or directory");
• use the relevant object in the code, e.g. wherever there is a call to getErrno() or strerror(), use an instance of ErrnoError instead.

Ok, working on it.

for now, just create the classes, don't worry about changing all the other code to use them yet. Let me look at the classes you create and we'll refine them before you change all the other code.

Please visit https://github.com/udit043/resiprocate/tree/patch-6
I have created new branch and implement class and mapping for this task. After discussion with mentor will close and create new pull request.

Udit, can you please create a new pull request for me to comment on?