object-lifetime

std::string getMyString() { return <make a string>; } ... HANDLE something = OpenSomething(getMyString().c_str(), ...); I've read Guaranteed lifetime of temporary in C++ and I believe that the temporary string will live until the assignment has been evaluated, i.e. plenty long enough to make this work as expected. Having once before run into an std::string lifetime-related bug (can't remember what it was) I'd rather double-check... Yes, this is fine. :-) The string will be destroyed at the end of the statement, at the semi colon. The destructor for the temporary will not be called until after

This is a fairly fine point, and I expect the answer is "it's not a hot idea to begin with" - that said, it has a points that I'm interested in regardless, if someone is kind enough to indulge. Model Code: public partial class MyEntities : ObjectContext { // the idea is if the object is in a using block, this always gets called? protected override void Dispose(bool disposing) { this.SaveChanges(); base.Dispose(disposing); } } Client Code: using(var model = new MyEntities()) { // do something // no worry about calling model.SaveChanges() } The issues I'm uncertain about are: Is Dispose the

What are the lifetimes of Qt Objects? Such as: QTcpSocket *socket=new QTcpSocket(); When socket will be destroyed? Should I use delete socket; Is there any difference with: QTcpSocket socket; I couldn't find deep infromation about this, any comment or link is welcomed. Qt uses parent-child relationships to manage memory. If you provide the QTcpSocket object with a parent when you create it, the parent will take care of cleaning it up. The parent can be, for example, the GUI window that uses the socket. Once the window dies (i.e. is closed) the socket dies. You can do without the parent but

As far as I understand the wording in 5.2.9 Static cast, the only time the result of a void* -to-object-pointer conversion is allowed is when the void* was a result of the inverse conversion in the first place. Throughout the standard there is a bunch of references to the representation of a pointer, and the representation of a void pointer being the same as that of a char pointer, and so on, but it never seems to explicitly say that casting an arbitrary void pointer yields a pointer to the same location in memory, with a different type, much like type-punning is undefined where not punning

I have a bug in my code that made me think I don't fully understand the Android Lifecycle. Yes, I have read all the docs and looked at the diagrams, but they seem to talk only about when to save data, when the activity may loose focus or get killed. However, my question is if I don't need to save state, what happens to the variables & their stored values? I expected them to be destroyed to, but a bug in my code seems to indicate otherwise. In my case here is what happened. I have an activity that launches a custom view (no xml, I just draw bitmaps on the screen in my custom view). The only