2009/5/6
Hi list,
In 'classic' C++ style I have signalled optional parameters in a function with pointers that might be null (I wouldn't like to create overloads for all possible combination of existing and non-existing parameters) e.g.
// p1 is mandatory, p2, p3 and p4 are optional void f(const Param1& p1, const Param2* p2, const Param3* p3, const Param4* p4);
And call it Param1p1; Param2 p2; Param4 p4; f(p1, &p2, 0, &p4);
I thought I could use boost::optional like this
void f(const Param1& p1, const boost::optional<Param2> & p2, const boost::optional<Param3> p3, const boost::optional<Param4> & p4);
And call it Param1p1; Param2 p2; Param4 p4; f(p1, boost::optional<Param2>(p2), boost::optional<Param3>(), boost::optional<Param4>(p4) );
It's less efficient, because all arguments will be copied. It's also more typing, longer compilation times and more code generated. Roman Perepelitsa.