袁晓辉 wrote:
Dear boost-users:
I am really sorry for asking shch a silly question, but I really need your help!
boost::lexical_cast is a great function to do casting. If I want is to cast from string to a "long long" type value, I can use the follow:
long long llVar = lexical_cast<long long>("123456789");
It is alright in this circs, but what if:
lexical_cast<long long>("9999999999999999999999999999999999999999999999999999999999999999999999999999");
This is an obvious overflow, but I have no way to handle this error, it returns a wrong number without throwing an exception!
Any suggestion? Thank you very much!!! Kevin
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I tested your example with VC++ 7.1, and it throws a bad_lexical_cast. The problem you have has nothing to do with lexical_cast. lexical_cast uses streams to do the conversion. It seems that you use an implementation of the C++ standard library with poorly implemented streams. I see two options: 1. Write your own conversion routine by hand. (Not that hard.) 2. Get a better implementation of the C++ standard library. You can not use atoi, for its behaviour is unspecified when the conversion can not be carried out. --Johan Råde