this is my my first post to a newsgroup, so i hope it will work... I use the boost regex library, and i was wondereing, why the following code doesn't work. When i output the result of the match, it should output "a", but it didn't, the output was something wrong like "yl". I figured out, that the reasen for this is, that the string sSearchString is just in the scope of the try-block, so it is allready destroyed when i do the output. If i put the declaration of the string above the try block, all works fine, because the searchstring is still existing when i do the output. The matchresult seems to save just a reference to the string. Am i doing sth wrong? I think this is quite dangerous, or is there a way to do this more safe?
It's not a reference: the match_results stores *a pair of iterators* into the string being searched. These are valid only for as long as the string from which they originate is both valid *and unmodified*. This is standard iterator behaviour, and I suggest you read up on the STL and iterators if you're not familiar with these already. The alternative - storing a copy of the string - is both hugely expensive in comparison, and throws away important positional information. If you want to keep around the strings that matched, it's up to you to copy them. Regards, John.