https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110190
Bug ID: 110190
Summary: regex: incorrect match results on DFA engines
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: mimomorin at gmail dot com
Target Milestone: ---
libstdc++ makes incorrect matches with the sample code in
https://en.cppreference.com/w/cpp/regex/syntax_option_type . (Though the
description of the "leftmost longest rule" is not correct in that page, their
expected results are fine).
Here is a slightly shorter version:
#include <iostream>
#include <string>
#include <regex>
int main()
{
std::string text = "regexp";
std::regex re(".*(ex|gexp)", std::regex::extended);
std::smatch m;
std::regex_search(text, m, re);
std::cout << m[0] << '\n'; // => should be "regexp" on DFA engines
}
This should print "regexp", but libstdc++ prints "regex". (libc++ works fine.)
