title: Logging from within a C++ Windows DLL file
body: <p>What is the best practice of logging DLL activity and internal parameter values.
  I wrote a DLL that is used by a few applications I wrote. Lately, some users were complaining about problems that I suspect are related to this DLL but I cannot reproduce on my dev machine.
  I'd like send them an equivalent DLL file that will log its activity, such as function calls, function return values and some internal parameters.
  I don't think there should be a problem for a DLL to create a log file and write to it. Is there a common practice related to this issue. Is there a standard place to write the data to?</p>