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[Bug libstdc++/63631] std::regex_match yielding inexplicable garbage; invalid reads in valgrind
- From: "redi at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 23 Oct 2014 16:59:29 +0000
- Subject: [Bug libstdc++/63631] std::regex_match yielding inexplicable garbage; invalid reads in valgrind
- Auto-submitted: auto-generated
- References: <bug-63631-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63631
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|FIXED |INVALID
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
sregex_iterator::operator->() yields a smatch_results and smatch_results::str()
yields a temporary string.
The reason is that smatch_results doesn't contain strings, it contains
iterators into some other string. When you want to retrieve a match it
constructs a new string from the relevant iterators. That avoids having to
construct all the strings up front when they may never be needed.