c++-faq

If I have a C++11 program running two threads, and one of them throws an unhandled exception, what happens? Will the entire program die a fiery death? Will the thread where the exception is thrown die alone (and if so, can I obtain the exception in this case)? Something else entirely? Nothing has really changed. The wording in n3290 is: If no matching handler is found, the function std::terminate() is called The behavior of terminate can be customized with set_terminate , but: Required behavior : A terminate_handler shall terminate execution of the program without returning to the caller. So

What C++ idioms should C++ programmers know? By C++ idioms, I mean design patterns or way of doing certain things that are only applicable for C++ or more applicable for C++ than most other languages. Why one should use the idioms, and what do the idioms accomplish? Here is one list . If I had to pick a couple I might go with the Curiously Recurring Template Pattern or Virtual Contstructors. By far the single most important "pattern" to learn and know that's (nearly) unique to C++ is RAII (Resource Acquisition Is Initialization). Edit: (To answer extra question edited into the question). You

With the new standard, there are new ways of doing things, and many are nicer than the old ways, but the old way is still fine. It's also clear that the new standard doesn't officially deprecate very much, for backward compatibility reasons. So the question that remains is: What old ways of coding are definitely inferior to C++11 styles, and what can we now do instead? In answering this, you may skip the obvious things like "use auto variables". Sumant Final Class : C++11 provides the final specifier to prevent class derivation C++11 lambdas substantially reduce the need for named function

Resource Acquisition is Initialization (RAII) is commonly used in C++ to manage the lifetimes of resources which require some manner of cleanup code at the end of their lifetime, from delete ing new ed pointers to releasing file handles. How do I quickly and easily use RAII to manage the lifetime of a resource I acquire from a C-style API? In my case, I want to use RAII to automatically execute a cleanup function from a C-style API when the variable holding the C-style resource it releases goes out of scope. I don't really need additional resource wrapping beyond that, and I'd like to minimize

C++2003 8.5/5 says: To default-initialize an object of type T means: — if T is a non-POD class type (clause 9), the default constructor for T is called (and the initialization is ill-formed if T has no accessible default constructor); — if T is an array type, each element is default-initialized; — otherwise, the object is zero-initialized . [Emphasis added.] The C++2011 standard changed that last item to — otherwise, no initialization is performed . This seems like it would be a breaking change for some programs. Was this intentional? Edit Here's some code to motivate this question: class Foo

Are the stages of compilation of a C++ program specified by the standard? If so, what are they? If not, an answer for a widely-used compiler (I'd prefer MSVS) would be great. I'm talking about preprocessing, tokenization, parsing and such. What is the order in which they are executed and what do they do in particular? EDIT: I know what compilation, linking and preprocessing do, I'm mostly interested in the others and the order. Explanations for these are, of course, also welcomed since I might not be the only one interested in an answer. Keith Thompson Are the stages of compilation of a C++

While I was trying to learn about C++ operators, I stumbled upon a strange comparison operator on cppreference.com , * in a table that looked like this: "Well, if these are common operators in C++, I better learn them", I thought. But all my attempts to elucidate this mystery were unsuccessful. Even here, on Stack Overflow I had no luck in my search. Is there a connection between <=> and C++ ? And if there is, what does this operator do exactly? * In the meantime cppreference.com updated that page and now contains information about the <=> operator. This is called the three-way comparison

Can we restrict variadic template arguments to a certain type? I.e., achieve something like this (not real C++ of course): struct X {}; auto foo(X... args) Here my intention is to have a function which accepts a variable number of X parameters. The closest we have is this: template <class... Args> auto foo(Args... args) but this accepts any type of parameter. Yes it is possible. First of all you need to decide if you want to accept only the type, or if you want to accept a implicitly convertible type. I use std::is_convertible in the examples because it better mimics the behavior of non

I was reading this and unfortunately could not understand in depth why the compiler does not allow conversion from Derived** to Base**. Also I have seen this which gives no more info than the parashift.com's link. EDIT: Let us analyze this code line by line: Car car; Car* carPtr = &car; Car** carPtrPtr = &carPtr; //MyComment: Until now there is no problem! Vehicle** vehiclePtrPtr = carPtrPtr; // This is an error in C++ //MyComment: Here compiler gives me an error! And I try to understand why. //MyComment: Let us consider that it was allowed. So what?? Let's go ahead! NuclearSubmarine sub;