template<typename T> T* Push(T* ptr); template<typename T> T* Push(T& ref); template<typename T, typename T1> T* Push(T1&& ref); I have int i = 0; Push<int>(i); But the compiler calls it ambiguous. How is that ambiguous? The second function is clearly the preferred match since it's more specia...
I recently tried to use Qt Creator 1.3.2 / Qt 4.6.2 / gcc 4.4.0 (32-bit version) on Windows 7 (64-bit) to compile an application using some of the experimental C++0x extensions and encountered the following (fatal) error: This file requires compiler and library support for the upcoming ISO C++ standard, C++0x. This support is currently ...
n3092 (final draft) says, under 5.17/9 A braced-init-list may appear on the right-hand side of - an assignment to a scalar [...] - an assignment defined by a user-defined assignment operator [..] While in GCC 4.5.1-pre9999, I can compile this (using -std=c++0x, NOT -std=gnu++0x) #include <iostream> int main() { ...
I am trying to pass a lambda expression to a function that takes a function pointer, is this even possible? Here is some sample code, i'm using VS2010: #include <iostream> using namespace std; void func(int i){cout << "I'V BEEN CALLED: " << i <<endl;} void fptrfunc(void (*fptr)(int i), int j){fptr(j);} int main(){ fptrfunc(func,...
I want to use gcc 4.4 or greater for iphone developement. anyone know how? ...
It took me quite some time to understand the difference between an rvalue and a temporary object. But now the final committee draft states on page 75: An rvalue [...] is an xvalue, a temporary object or subobject thereof, or a value that is not associated with an object. I can't believe my eyes. This must be an error, right? To ...
I am trying to find out if there is an actual computational benefit to using lambda expressions in c++, namely "this code compiles/runs faster/slower because we use lambda expressions" OR is it just a neat development perk open for abuse by poor coders trying to look cool? Thanks. PS. I understand this question may seem subjective but ...
I used to write code like this: class P {}; class Q: public P {}; class A { // takes ownership A(P* p): p_(p) {} scoped_ptr<P> p_; }; A a(new Q); With C++0x, should I rewrite class A as: class A { // takes ownership A(unique_ptr<P>&& p): p_(move(p)) {} unique_ptr<P> p_; }; ...
In C++0x, methods can be overloaded on whether or not the expression that denotes the object on which the method is called is an lvalue or an rvalue. If I return *this from a method called via an rvalue, do I need to explicitly move from *this or not? Foo Foo::method() && { return std::move(*this); // Is this move required or not?...
why aren't strongly typed C++0x enumerations comparable to each other? ...
Rvalues IMHO are great improvement in C++, but at the beginning the're seems quite. Please look at code below: #include <string> std::string && foo (void) { std::string message ("Hello!"); return std::move (message); } void bar (const std::string &message2) { if (message2 == "Bye Bye!") return; } int main () { ...
I want to play with constexpr, does any compiler support it yet? ...
Hi everyone, Summer is coming, and a group of friends and I are getting ready for it :) We decided to build a compile-time Arbitrary precision Unsigned Integers. We would like to provide a set of integers algorithms(functions) with the library. We have seen a number of requests for such a library(SoC2010, C++0x Standard Library wishlis...
If my command line is: > prog --mylist=a,b,c Can Boost's program_options be setup to see three distinct argument values for the mylist argument? I have configured program_options as: namespace po = boost::program_options; po::options_description opts("blah") opts.add_options() ("mylist", std::vector<std::string>>()->multitoken, ...
What does an r-value reference look like from a lower-level perspective. I just can't seem to wrap my head around it! Can I see an example of generated code (either equivalent C or x86/x64) from a r-value reference vs. a l-value reference? For example, what would this construct look like? Let's assume no copy elision for now. vector<So...
Hi all, I've recently started using Boost.Asio in a project and would like to know whether anyone knows a clean solution to transfer ownership of a newly created socket to tcp::acceptor::async_accept, which would in turn transfer this ownership to the accept handler function. This isn't an incoherent desire, mind you, since the handler...
Suppose I have the following two data structures: std::vector<int> all_items; std::set<int> bad_items; The all_items vector contains all known items and the bad_items vector contains a list of bad items. These two data structures are populated entirely independent of one another. What's the proper way to write a method that will retu...
The min algorithm is normally expressed like this: template <typename T> const T& min(const T& x, const T& y) { return y < x ? y : x; } However, this does not allow constructs of the form min(a, b) = 0. You can achieve that with an additional overload: template <typename T> T& min(T& x, T& y) { return y < x ? y : x; } What ...
I don't understand the last line of the example on page 148 of the FCD (§7.6.1.2/4): const int&& foo(); int i; struct A { double x; }; const A* a = new A(); decltype(foo()) x1 = i; // type is const int&& decltype(i) x2; // type is int decltype(a->x) x3; // type is double decltype((a->x)) x4 = x3; // type is co...
What is the difference between Scala traits Haskell type class and C++0x Concepts? ...