Hi all, I'm using regexp from boost-1.28 and experience the following behavior. Consider the following (somewhat artificial) regexp pattern: a{1}b As I expected, that pattern is found in "ab" but not "aab". To my suprise however, the same pattern *is* found in "aaab", "aaaaab", and any other string consisting of an odd number of "a"s followed by a "b". It is not found in strings consisting of an even number of "a"s followed by a "b". This seems odd (no pun intended). I see the same sort of behavior with quantifiers other than "{1}" and where the quantified expression matches other single characters. (Oddly enough, the behavior changes when using a quantified expression that matches multiple characters. "(ab){1}c" is found in "abc", "ababc", "abababc", and any other string containing "abc".) FWIW, I first observed the behavior when trying to find social security numbers with the following pattern: \d{3}-\d{2}-\d{4} As expected, that pattern was found in "123-12-1234" but not in "1234- 12-1234". However it *was* found in "1234567-12-1234". Is this behavior by design or is it a bug? If it's a bug, has it been fixed in a subsequent boost release? Also what is the correct behavior? Should "a{1}b" be found in "aab" (albeit starting at the second character)? FWIW, it's easy enough for me to workaround the current behavior with a pattern like this: (^|[^a])a{1}b Thanks, --Dean