Implicit garbage collection could have been added in, but it just didn’t make the cut. Probably due to not just implementation complications, but also due to people not being able to come to a general consensus fast enough. A quote from Bjarne Stroustrup himself: I had hoped that a garbage collector which could be optionally … Read more
Some people do not have the luxury of using std::vector, even with allocators. Some people need a dynamically sized array, so std::array is out. And some people get their arrays from other code that is known to return an array; and that code isn’t going to be rewritten to return a vector or something. By … Read more
A lambda can only be converted to a function pointer if it does not capture, from the draft C++11 standard section 5.1.2 [expr.prim.lambda] says (emphasis mine): The closure type for a lambda-expression with no lambda-capture has a public non-virtual non-explicit const conversion function to pointer to function having the same parameter and return types as … Read more
The answer is a definite yes. On the plus side there is: Code that previously implicitly copied objects will now implicitly move them when possible. On the negative side, several examples are listed in the appendix C of the standard. Even though there are many more negative ones than positive, each one of them is … Read more
Compile the program with: g++ -Wall -Wextra -Werror -c main.cpp -o main.o ^^^^^^^^^^^^^^^^^^^^ <- For listing all warnings when your code is compiled. as cout is present in the C++ standard library, which would need explicit linking with -lstdc++ when using gcc; g++ links the standard library by default. With gcc, (g++ should be preferred … Read more
It’s compiler dependent. That said, in general using ” prioritizes headers in the current working directory over system headers. <> usually is used for system headers. From to the specification (Section 6.10.2): A preprocessing directive of the form # include <h-char-sequence> new-line searches a sequence of implementation-defined places for a header identified uniquely by the … Read more
It requires mutable because by default, a function object should produce the same result every time it’s called. This is the difference between an object orientated function and a function using a global variable, effectively.
The standard has been changed since the question (and most answers) were posted in the resolution of this defect report. The way to make a for(:) loop work on your type X is now one of two ways: Create member X::begin() and X::end() that return something that acts like an iterator Create a free function … Read more
Yes, the code is standard conforming. The + triggers a conversion to a plain old function pointer for the lambda. What happens is this: The compiler sees the first lambda ([]{}) and generates a closure object according to ยง5.1.2. As the lambda is a non-capturing lambda, the following applies: 5.1.2 Lambda expressions [expr.prim.lambda] 6 The … Read more
Deleting a function is a C++11 feature: The common idiom of “prohibiting copying” can now be expressed directly: class X { // … X& operator=(const X&) = delete; // Disallow copying X(const X&) = delete; }; […] The “delete” mechanism can be used for any function. For example, we can eliminate an undesired conversion like … Read more