On quarta-feira, 22 de maio de 2013 16.52.29, Jonathan Greig wrote: > Thank you André. The dynamic_cast worked perfectly. I'm from a C background > and have been doing C-style casts for years without any major problems. > Apparently this guy has also:) > http://stackoverflow.com/questions/28002/regular-cast-vs-static-cast-vs-dyna > mic-cast
A C cast is equivalent to a chain of reinterpret_cast and const_cast. It does not do static casting or dynamic casting, which means it will not do pointer adjustments properly. So, as a rule of thumb: do not use C-style casts in C++ code and always use the least invasive C++ cast operator that you can use. And another rule of thumb: dynamic_casts are always checked[*], all the other casts are never checked. In your particular case, you're doing something really obscure and rare: a cross-cast between two unrelated types. Only dynamic_cast can accomplish that. So a C-style cast will never work. It would be possible to do it with a static_cast or a C-style class if you cast to your base type that derives from both QGraphicsItem and BaseObject. [*] there are two exceptions, which are when you have to use dynamic_cast yet you know that it will succeed: cast to through virtual inheritance or your case. -- Thiago Macieira - thiago.macieira (AT) intel.com Software Architect - Intel Open Source Technology Center
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