ATL regular expression code adds dump/debug capabilities with ATL_REGEXP_DUMP preprocessor definition defined (undocumented). Dump output is directed to stdout, so if the application is not console, it has to be redirected in advance, e.g. into a $(BinaryPath)$(BinaryName)-atlrx.h file. CAtlRegExp<> Expression; LPCTSTR pszPattern; BOOL bCaseSensitive; #if defined(ATL_REGEXP_DUMP) REParseError Error = Expression.Parse(pszPattern, bCaseSensitive); if(Error != REPARSE_ERROR_OK) {…