Bugs item #917070, was opened at 2004-03-15 21:44 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=107586&aid=917070&group_id=7586 Category: lexical_cast Group: None Status: Open Resolution: None Priority: 5 Submitted By: John F Meinel Jr (jfmeinel) Assigned to: Kevlin Henney (kevlin) Summary: Bug in lexical_cast.hpp Initial Comment: In boost-1_31_0, I believe there is a typo in lexical_cast.hpp The line Target lexical_cast(Source arg) should be Target lexical_cast(Source& arg) Otherwise it actually creates a copy of the argument before doing the lexical cast. This causes problems if you try to lexical_cast() a virtual object. Here is code that shows the bug. By just adding the '&', the code performs as you would expect it to. #include <iostream> #include <string> #include <boost/lexical_cast.hpp> struct A { virtual int f() const = 0; }; struct B : A { virtual int f() const { return 1; } }; struct C : B { virtual int f() const { return 2; } }; std::ostream& operator<<(std::ostream& os, const A& a) { return os << a.f(); } int main() { C c; std::string s; std::cout << c << std::endl; //This should print 2 s = boost::lexical_cast<std::string>(c); std::cout << s << std::endl; //This should print 2 s = boost::lexical_cast<std::string, B>(c); std::cout << s << std::endl; //This returns 1, not 2 //This fails because it tries to instantiate an object of type A. Why??? s = boost::lexical_cast<std::string, A>(c); std::cout << s << std::endl; } ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=107586&aid=917070&group_id=7586 ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ Boost-bugs mailing list Boost-bugs@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/boost-bugs