id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
2340	Regex : Invalid preceding regular expression problem	jcombe@…	John Maddock	"I have the following code:-

std::cout << ""BUILD REGEX"" << std::endl;
try
{
   boost::u32regex uregex= boost::make_u32regex ( ""(.*?)(\\b?\\s?)(\\w*?)&(\\w+?)(\\b\\s?&?)(.*)"" , boost::regex::perl );
}
catch ( boost::regex_error x )
{
   std::cout << ""REGEX ERROR ["" << x.what() << ""]"" << std::endl;
   return false;
}
std::cout << ""REGEX BUILT"" << std::endl;
return false;

When I compile this code and then run it, it throws an exception and prints this message:-

REGEX ERROR [Invalid preceding regular expression]

When I use this line instead

   boost::u32regex uregex= boost::make_u32regex ( ""(.*?)(\\b\\s?)(\\w*?)&(\\w+?)(\\b\\s?&?)(.*)"" , boost::regex::perl );

It does work.

Both regular expressions compile and run as I expect in Perl. Is it a bug that this regex does not work in Boost?"	Bugs	closed	To Be Determined	regex	Boost 1.36.0	Problem	wontfix	regex