Use of C plus plus 11 features

See also https://github.com/crosswalk-project/crosswalk-website/wiki/Coding-Style-of-XWalk-for-Android

ML discussion https://lists.crosswalk-project.org/pipermail/crosswalk-dev/2014-March/001233.html

The consensus at the moment seems to be to allow use of C++0x features for extensions, as they typically are platform (and thus compiler) bound.

Chromium upstream

Currently, chromium officially does not support c++11 because of gcc on linux, cros and android. https://groups.google.com/a/chromium.org/forum/?fromgroups=#!searchin/chromium-dev/space$20android/chromium-dev/oVTPsijC7d0/WDcnq3AyE4gJ

• windows: msvs2012
• mac: clang
• linux: gcc4.7, clang
• chromeos: gcc4.7
• android: gcc4.6

After every platforms support gcc 4.8, chromium would support c++11.

Gcc 4.6 features (relevant for Android)

http://gcc.gnu.org/gcc-4.6/cxx0x_status.html

Notable:

• Initializer lists

struct S {
    S(std::initializer_list<int>) { /* ... */ }
};
S s = { 1, 2, 3 };

• auto-typed variables

auto i = 1;

• Lambdas

std::list<int> l({ 1, 2, 3} );
std::for_each (l.begin(),
               l.end(), 
               [](int i) {
                    std::cout << i << std::endl;
               });

• Null pointer constant

char *c = nullptr;

• Strongly-typed enums

// Old-style enums would not allow value names being re-used. 
enum class Colors { Black, White, Red, Green, Blue };
enum class Monochrome { Black, White };

• Unicode and raw string literals

const char *c = u8"Hêllo Wörld";

• Range-based for

int array[] = { 1, 2, 3, 4, 5 };
for (int& i : array)
    std::cout << i << std::endl;

Gcc 4.7 features (relevant for Linux)

http://gcc.gnu.org/gcc-4.7/cxx0x_status.html

Changes over 4.6 http://gcc.gnu.org/gcc-4.7/changes.html#cxx

Notable:

• Explicit virtual override

// This will not compile, since Derived::f() overloads, not overrides.
struct Base {
    virtual void f();
};
struct Derived : Base {
    virtual void f(int i) override;
};

• Non-static data member initializers

struct S {
    int magic = 42;
};

• Delegating constructors

struct S {
    S(int i) : _i(i) {};
    S() : S(42) {}
private:
    int _i;
};