I had some issues getting robust behaviour from the WriteConsoleW call. There appear to be internal buffers allocated by the WriteConsole call which are dependant on the amount of data passed in the first (?) call.
The longest string that I was able to write out successfully on the first call to WriteConsole was 30,704 chars long, rather an odd limit. With this as the first call subsequent calls of up to the same length also succeeded. However if the first call was with a string of 15,000 chars and the second was of 20,000 chars, then the second call would fail with last error 8 (Not enough storage is available to process this command). To resolve this I have changed the implementation to use WriteFile rather than WriteConsole. WriteFile supports partially writing from a buffer (WriteConsoleW has a lpNumberOfCharsWritten param which could do this, but it doesn't seem to ever partially write). The .NET Console class provides a Stream instance that wraps up all the WriteFile calls. This change is now committed to CVS. In my testing this works at least up to 5,000,000 char output strings. Nicko > -----Original Message----- > From: Wesley Smith [mailto:[EMAIL PROTECTED] > Sent: 28 January 2005 22:45 > To: Log4NET Dev > Subject: RE: Patch to allow large messages to be logged via > ColoredConsoleAppender > > From the documentation, I thought that 31999 characters would > work too, but I found that it didn't always work. At least > with my test case, if the first call to WriteConsoleW is > smaller than 26000ish, then you can call it subsequent times > with up to 31999 chars, but if the first call is with > anything > 26000ish, then it prints nothing (for example, > passing 30000 characters to the first call of WriteConsoleW > doesn't print anything - at least in my test it didn't). > > I don't understand this behavior, and hope that you can come > up with something more reasonable and understandable - just > wanted to warn you to be on the lookout for this weird behavior. > > > > > -----Original Message----- > > From: Nicko Cadell [mailto:[EMAIL PROTECTED] > > Sent: Friday, January 28, 2005 2:35 PM > > To: Log4NET Dev > > Subject: RE: Patch to allow large messages to be logged via > > ColoredConsoleAppender > > > > It looks like the buffer passed to WriteConsoleW is limited > to 64KB, > > i.e. 32000 WCHARs less 1 for the NULL if the P/Invoke marshalling > feels > > like putting one on the end of the string. > > > > I will update the appender along the lines of your patch. > > > > > > Thanks, > > Nicko > > > > > -----Original Message----- > > > From: Wesley Smith [mailto:[EMAIL PROTECTED] > > > Sent: 27 January 2005 20:03 > > > To: log4net-dev@logging.apache.org > > > Subject: Patch to allow large messages to be logged via > > > ColoredConsoleAppender > > > > > > I found that if you attempt to log a message of more than about > > > 26000 characters, ColoredConsoleAppender will not log the message > > > (no error, just silently eats the message). One possible fix for > > > the problem is given in the patch below: > > > > > > > > > --- > C:\TEMP\log4net-1.2.0-beta8\src\Appender\ColoredConsoleAppender.cs > > > Mon Jul 07 01:05:02 2003 > > > +++ C:\Program > > > Files\log4net\log4net-1.2.0-beta8\src\Appender\ColoredConsoleA > > > ppender.cs > > > Wed Jan 26 12:57:22 2005 > > > @@ -280,13 +280,32 @@ > > > > > > string strLoggingMessage = > > > RenderLoggingEvent(loggingEvent); > > > > > > - // write the output. > > > UInt32 uiWritten = 0; > > > + > > > + // WriteConsoleW can only handle a limited > > > number of characters at a time > > > + // and emperically, 26000 is about right. > > > + const int maxChunkSize = 26000; > > > + while (strLoggingMessage.Length > maxChunkSize) > > > + { > > > + string firstPart = > > > strLoggingMessage.Substring(0, maxChunkSize); > > > + WriteConsoleW( iConsoleHandle, > > > + firstPart, > > > + (UInt32)firstPart.Length, > > > + out (UInt32)uiWritten, > > > + IntPtr.Zero); > > > + > > > + // Remove the characters already output > > > from strLoggingMessage > > > + strLoggingMessage = > > > strLoggingMessage.Substring(maxChunkSize); > > > + > > > + } > > > + // write the remaining output. > > > + > > > WriteConsoleW( iConsoleHandle, > > > > > > strLoggingMessage, > > > > > > (UInt32)strLoggingMessage.Length, > > > out > > > (UInt32)uiWritten, > > > IntPtr.Zero); > > > + > > > } > > > > > > /// <summary> > > > >
