[Boost-users] Re: regex bug (regex_search throws bad_expression)

starts and ends with repeats either of which can match repeated whitespace - this is what causes the matcher to thrash trying to find a match, eventually leading to it giving up and throwing an exception, I think you could make your expression much more precise by using:

regex re("([^\n]*\\n+)+\\s+NEEDEDSUBITEM2:[^\\s]");

By moving the \s+ out side of the repeat like this the expression is now much more deterministic - it can only do one thing for any given input character.

indeed refactoring the expression solved the problem, thanks! adam