🚀 go-pugleaf

> what is the best approach to implement a Logging Functionality within
> my application? I need this for debuging purposes for end user. So
> that when an error occur, end user can send me the log file to
> inspect.
>
> Also, is there a why to enable / disable this functionality? For
> example depending on the command line options used to start the
> application.


i have library function:

procedure LogToFile(filename: string; const s: string);
var
     f: Textfile;
     FilePath: string;
begin
    FilePath := ExtractFilePath(filename);
     if not DirectoryExists(FilePath) then
          CreateDir(FilePath);

     System.Assign(f, filename);
     if FileExists(filename) then
          System.Append(f)
     else
          Rewrite(f);
     try
        WriteLn(f, S);
     finally
          System.Close(f);
     end;
end;


i usually then create a procedure in the application:

procedure FileLog(const LogString: string);
var
     szLogFile: string;
begin
     szLogFile := 
ExtractFilePath(ParamStr(0))+'Logfiles\'+FormatDateTime('yyyymmdd', 
Now)+'.log';
      {The zero-th parameter to an application is, by convention, the
           appliation's path and filename. But since you cannot trust this 
value,
           you should use GetModuleFilename instead.
         Fortunatly, ParamStr() detects if you want the zero-th parameter
       and instead calls GetModuleFilename. As a result, it is safe and 
proper
       to use ParamStr(0) to get our image filename}

     LogToFile(szLogFile, DateTimeToISOStr(Now)+' '+LogString);
end;



This way the logfile rolls over each day, and it handily sitting in a 
Logfiles folder.

Although this is bad bad for anyone running as a standard user under XP, and 
should use SHGetFolderPath to store the log files in the user's local (i.e. 
non-roaming) application data folder (CSIDL_LOCAL_APPDATA). e.g.:
    c:\documents and settings\Monzer\Local Settings\Application Data
    c:\users\monzer\appdata\local

The call to SHGetFolderPath is left as an excercise for the reader :)