[Boost-users] Re: Regex trouble (compiling a simple expression fails)

From: Eric Niebler (eric_at_[hidden])
Date: 2005-04-05 09:34:40

Bogdan Harjoc wrote:
> Hi,
> 
> I've looked at replacing the pcre library with boost regex,mainly
> because the C++ interface seems more usable than the plain C functions
> from pcre.
> 
> The trouble is, I'm wasn't able to adjust regular expressions to the
> format boost regex uses. For instance, while pcre and others seem to
> like the expression "\?", boost throws bad_expression. The same goes
> for "\(", "\+" and others I'm using.
> 

You need to escape the escape. "\\?" will match a literal '?' character. 
Ditto for "\\(" and "\\+". That's because the C++ compiler will eat one 
level of escape even before the regex engine sees it.

Surely you have to use an extra slash with PCRE, too, right?

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com