If you have Compiler.ViewSeparateLogs: FALSE set in your profile, then if there are any error messages from the compiler, an ErrorLog button will appear at the top of the source viewer. The first click on this button brings up a viewer with the error log messages. Succeeding clicks will call any procs that you register with RegisterErrorLogProc. Those procs will get called with the arguments from the button click (which button, any modifiers), the error log viewer and also an argument repeat, which is false the first time the ErrorLogProc proc is called, and is true thereafter until the next compilation is done. Thus an ErrorLogProc only needs to actually parse the errors when repeat is false.

Error log parsers should be put into CedarChest/ErrorLogParsers. Running CycleThruErrorLog in that directory will install a simple parser.