Actually, now that I look at the code, should it simply be

< if(((m_match_flags & match_not_null) == 0) && (m_presult->length() == 0)) ---

...

if(((m_match_flags & match_not_null) == 0) && (m_result.length() ==

0))

just below the original patch? That _seems_ to work.

Almost, here's the complete patch going into cvs now: $ cvs diff -u johnmaddock@cvs.boost.sourceforge.net's password: cvs diff: Diffing . Index: perl_matcher_common.hpp =================================================================== RCS file: /cvsroot/boost/boost/boost/regex/v4/perl_matcher_common.hpp,v retrieving revision 1.18.2.1 diff -u -r1.18.2.1 perl_matcher_common.hpp --- perl_matcher_common.hpp 7 Apr 2004 11:03:31 -0000 1.18.2.1 +++ perl_matcher_common.hpp 9 Apr 2004 15:50:27 -0000 @@ -208,7 +208,7 @@ search_base = position = m_result[0].second; // If last match was null and match_not_null was not set then increment // our start position, otherwise we go into an infinite loop: - if(((m_match_flags & match_not_null) == 0) && (m_presult->length() == 0)) + if(((m_match_flags & match_not_null) == 0) && (m_result.length() == 0)) { if(position == last) return false; Index: regex_grep.hpp =================================================================== RCS file: /cvsroot/boost/boost/boost/regex/v4/regex_grep.hpp,v retrieving revision 1.6 diff -u -r1.6 regex_grep.hpp --- regex_grep.hpp 4 Oct 2003 11:28:56 -0000 1.6 +++ regex_grep.hpp 9 Apr 2004 15:50:27 -0000 @@ -55,23 +55,23 @@ return count; // we've reached the end, don't try and find an extra null match. if(m.length() == 0) { + if(m[0].second == last) + return count; // we found a NULL-match, now try to find // a non-NULL one at the same position: - BidiIterator last_end(m[0].second); - if(last_end == last) - return count; + match_results<BidiIterator, match_allocator_type> m2(m); matcher.setf(match_not_null | match_continuous); if(matcher.find()) { ++count; - last_end = m[0].second; + //last_end = m[0].second; if(0 == foo(m)) return count; } else { // reset match back to where it was: - m.set_second(last_end); + m = m2; } matcher.unsetf((match_not_null | match_continuous) & ~flags); }