I have written a console application that makes use of console.write and console.writeline to provide some logging. The application is a server application that uses asynchronous beginacceptconnection() and beginread() ( Sockets ) for communication. Occasionally i get reports of it hanging and from the limited debug i can do i am able to see the problem being Console.Writeline() or Console.write().
Being multi-threaded I have been careful to have a lock around the logging class so only one thread can log a message at once.....when I've caught a hang all i get are threads blocking on the lock and VS reporting that the control has passed into Console.Write and it is waiting for it to come back....it never does.
A couple of days ago i got another report of a failure but this time during bootup....where no asynch connections have yet been kicked off( the main thread does spawn a thread to bootup though ) and I was sent a picture.....see below.( i added the begin and end critical section lines to prevent this and it did not )
// Logging Class
public class Logging
{
// Lock to make the logging class thread safe.
static readonly object _locker = new object();
public delegate void msgHandlerWriteLineDelegate(string msg, Color col);
public static event msgHandlerWriteLineDelegate themsgHandlerWriteLineDelegate;
public delegate void msgHandlerWriteDelegate(string msg, Color col);
public static event msgHandlerWriteDelegate themsgHandlerWriteDelegate;
public static void Write(string a, Color Col)
{
if (themsgHandlerWriteDelegate != null)
{
lock (_locker)
{
themsgHandlerWriteDelegate(a, Col);
}
}
}
public static void Write(string a)
{
if (themsgHandlerWriteDelegate != null)
{
lock (_locker)
{
themsgHandlerWriteDelegate(a, Color.Black);
}
}
}
public static void WriteLine(string a, Color Col)
{
if (themsgHandlerWriteLineDelegate != null)
{
lock (_locker)
{
themsgHandlerWriteLineDelegate(a, Col);
}
}
}
public static void WriteLine(string a)
{
if (themsgHandlerWriteLineDelegate != null)
{
lock (_locker)
{
themsgHandlerWriteLineDelegate(a, Color.Black);
}
}
}
// Console Methods That implement the delegates in my logging class.
public static void ConsoleWriteLine(string message, Color Col)
{
try
{
if (Col == Color.Black)
{
Console.ForegroundColor = ConsoleColor.Gray;
}
else
{
Console.ForegroundColor = (ConsoleColor)Enum.Parse(typeof(ConsoleColor), Col.Name);
}
Thread.BeginCriticalRegion();
Console.WriteLine(message);
Thread.EndCriticalRegion();
Console.ForegroundColor = ConsoleColor.Gray;
}
catch (ThreadAbortException ex)
{
Console.WriteLine("ThreadAbortException : " + ex.Message);
}
catch (Exception ex)
{
Console.WriteLine("Exception : " + ex.Message);
}
}
public static void ConsoleWrite(string message, Color Col)
{
try
{
if (Col == Color.Black)
{
Console.ForegroundColor = ConsoleColor.Gray;
}
else
{
Console.ForegroundColor = (ConsoleColor)Enum.Parse(typeof(ConsoleColor), Col.Name);
}
Thread.BeginCriticalRegion();
Console.Write(message);//**THIS IS WHERE IS HANGS...IT NEVER RETURNS **
Thread.EndCriticalRegion();
Console.ForegroundColor = ConsoleColor.Gray;
}
catch (ThreadAbortException ex)
{
Console.WriteLine("ThreadAbortException : " + ex.Message);
}
catch (Exception ex)
{
Console.WriteLine("Exception : " + ex.Message);
}
}
public static void ConsoleUpdate(string message)
{
try
{
Thread.BeginCriticalRegion();
Console.WriteLine(message);//**THIS IS WHERE IS HANGS...IT NEVER RETURNS **
Thread.EndCriticalRegion();
}
catch (ThreadAbortException ex)
{
Console.WriteLine("ThreadAbortException : " + ex.Message);
}
catch (Exception ex)
{
Console.WriteLine("Exception : " + ex.Message);
}
}
// The main method...subscribes to delegates and spawns a thread to boot HW..main thread then exits.
public static void Main()
{
Logging.themsgHandlerWriteDelegate += new Logging.msgHandlerWriteDelegate(ConsoleWrite);
Logging.themsgHandlerWriteLineDelegate += new Logging.msgHandlerWriteLineDelegate(ConsoleWriteLine);
Logging.themsgHandlerUpdateDelegate += new Logging.msgHandlerUpdateDelegate(ConsoleUpdate);
}
}
public class ClassOnOtherThread
{
// In a different class running on a different thread the following line occasionly invokes the error:
private void BootHw(string Resource, string Resource2)
{
Logging.Write("\t\t[");
}
}
My reading of the MSDN suggests Console.WriteLine and Console.Write are threadsafe and therefore i don't actually need a lock around it....i also can't believe it Microsoft's code is wrong(;-) and so I am guessing it is some interaction my code is doing which creates the error.
Now my question : Should i be doing anything to prevent Console.WriteLine and Console.Write being interrupted?...it is my guess that something it interrupting it...but i don't really know that!!
Any help would me very much appreciated.
Regards,
Gordon.