Re: [Boost-Users] use of REGEX_SEARCH to match lookahed subexpression.

Search in the folowing strings (see below) using expression like: /exchange/test/(?!Drafts)/a.EML/b.png fails /exchange/test/Drafts/a.EML/b.gif /exchange/test/Inbox/a.EML/b.png /exchange/test/Inbox/a.EML/b.gif /exchange/test/Drafts/a.EML/b.png

At the same moment I can suceesfully search using the expression: /exchange/test/Inbox/a.EML/b.(?!png).

Remember that a lookahead assertion doesn't consume any characters, so for your expression to match it would have to find a string: /exchange/test//a.EML/b.png To do what you want, add a [^/]+ after the assertion: /exchange/test/(?!Drafts)[^/]+/a.EML/b.png Regards, John Maddock