nebulous TRACE output

[moredip]

Has anyone else noticed some output from TRACE seems to occasionally be dropped before it appears in the debug window? Am I paranoid? Am I covering my own programming inadequacies by blaming M$? TIA, Pete

[Shog9 0]

donno about that, but i've been bitten already by the size limit of presearved text in the output window; it just won't hold generated C source for a 4MB transparency LUT :(( Black rooms are calling; To men in leather coats. White labs are cooking up the silver ghost.

Smashing Pumpkins, Glass and the Ghost Children

[Roger Allen]

The input buffer size for the TRACE output window is a limited size (after all its a pipe between the processes). If your debug output TRACE volume is high and the thread reading the buffer in the VC editor does not run often enough, you can lose TRACE information from the window. So your not paranoid, if this is what is happening to you. Roger Allen Sonork 100.10016 If I'm not breathing, I'm either dead or holding my breath. A fool jabbers, while a wise man listens. But is he so wise to listen to the fool?

[moredip]

That sounds like what is happening. I'm writing LOADS of memory allocation info to the debug output to try and track down mem leaks. I guess the only solution would be to put a little pause in my AllocHook() after every TRACE(). Thanks Roger.

[Stephen C Steel]

No, you are probably getting bitten by a Visual Studio bug. Visual Studio filters the output of the OutPutDebugString() function, which the TRACE macro ultimately calls, before showing it in the output window in order to remove the application name (which otherwise gets added). However, the filtering is not too smart (at least with version 6.0), and it messes up the display of TRACE messages that includes both an open parenthesis "(" and a colon ":" in that order.

When I add the following lines to my code

TRACE (_T("Text before colon: Text after colon\n"));
TRACE (_T("Text with parenthesis() before colon: Text after colon\n"));
TRACE (_T("Text with open parenthesis( before colon: Text after colon\n"));
TRACE (_T("Text with close parenthesis) before colon: Text after colon\n"));
TRACE (_T("Text with (text inside parenthesis) before colon: Text after colon\n"));

the Visual Studio output window displays

Text before colon: Text after colon
Text with parenthesis() before colon
Text with open parenthesis( before colon
Text with close parenthesis) before colon: Text after colon
Text with (text inside parenthesis) before colon

Intrestingly, if I select this text text in the output window and paste it into notepad, I get

Text before colon: Text after colon
Text with parenthesis() before colonText with open parenthesis( before colonText with close parenthesis) before colon: Text after colon
Text with (text inside parenthesis) before colon

Stephen C. Steel Kerr Vayne Systems Ltd.

[Stephen C Steel]

No, you aren't being paranoid - there is a bug in Visual Studio version 6.0. The TRACE macro ultimately uses OutputDebugString(), and along the way the application name gets prepended to the output. Visual studio has a filter that attempts to strip the application name before showing the text in the output window, but it is buggy.

If I add the following code to my application

TRACE (_T("Text before colon: Text after colon\n"));
TRACE (_T("Text with parenthesis() before colon: Text after colon\n"));
TRACE (_T("Text with open parenthesis( before colon: Text after colon\n"));
TRACE (_T("Text with close parenthesis) before colon: Text after colon\n"));
TRACE (_T("Text with (text inside parenthesis) before colon: Text after colon\n"));

then the Visual Studio output window displays

Text before colon: Text after colon
Text with parenthesis() before colon
Text with open parenthesis( before colon
Text with close parenthesis) before colon: Text after colon
Text with (text inside parenthesis) before colon

Interestingly, if I select the text in the output window and paste it to notepad, I get

Text before colon: Text after colon
Text with parenthesis() before colonText with open parenthesis( before colonText with close parenthesis) before colon: Text after colon
Text with (text inside parenthesis) before colon

Stephen C. Steel Kerr Vayne Systems Ltd.

[moredip]

I don't think this is the issue in my case, as I'm not using paretheses. But thanks anyway, it's always useful to know stuff like that! Pete