Unit source code does not match code execution path when breakpoint hit

Question

I am debugging a DirectShow filter I created with the DSPACK code library using Delphi 6 Pro. When a breakpoint I set is hit in one particular unit named BaseClass.pas, and I begin tracing, the Execution Point jumps to strange places in the source code. This usually indicates that the source code being traced does not match the source code that was compiled into one of the packages being used by the Delphi application. Oddly enough it is only the BaseClass unit since I have traced other units belonging to the DSPACK code library and they do not exhibit this problem. I am not using run-time packages.

I scanned my disk and found only one copy of BaseClass.dcu with a modification date equal to the last time I built the program. I have not modified the source for that unit or any other belonging to DSPACK. Since my Filter is part of the main application this indicates that BaseClass.pas would be subject to a dual use situation since it is used to build the DSPACK component package (dpk), and is also referenced by my main application directly via the TBCSource object my Filter descends from. Note, I did try adding the unit PAS file directly to my Project but that didn't fix anything.

I also went back and re-opened each of the DSPACK package files and did a full re-build. None of this helped. Is there something else I can try to get the source synchronized with the compiled image of the BaseClass unit? Or is a different problem altogether and if so, what is it and how can I fix it?

Answer 1

Sometimes this happens when code is copied/pasted from web pages or other sources, and the lines don't end with CR/LF pairs (#13#10 or 0x0D0A, standard for Windows) but end in only LF (#10 or 0x0A, typically the line ending in *nix systems) or CR (#13 or 0x0D, typical with Mac OSX/iOS). The incorrect line terminators confuse the debugger - this has been an issue for the past several Delphi versions.

You can sometimes fix this by opening the source file using a text editor like Notepad, making a small meaningless change (insert and then delete a blank line, for instance), and then save the file.