page-fault

Removed or Fixed Language Features

Removed Elements

The following items have all been removed. We’d get build errors if we were using any of these under C++17, so we can be fairly certain that we’re not accidentally using them.

• The register did nothing since C++11, now it’s been removed.
• bool++ was deprecated in C++98, ++bool was deprecated in C++03. Both have been removed in C++17.
• Old-style exception specifications were removed as they were too impractical. throw() still remains, but and means the same as noexcept(true). noexcept is should be preferred.
  • throw() isn’t directly used in our repo, but is used by a couple of dependencies.
• No more trigraphs.

Fixes

Direct List Initialisation with auto

C++17 updates the type deduction rules for direct list initialisation.

auto item { 1.0f };     // direct initialisation, deduces type `float` since C++17
auto list = { 1.0f };   // copy initialisation, deduces type `std::initializer_list<float>`

• For direct initialisation from a braced-init-list with a single element, auto deduction will deduce the type of that element.
• For direct initialisation from a list with more than one element, auto deduction will be ill-formed.

auto x {1, 2}; // this will cause a compile error as of C++17

static_assert with No Message

Frequently, we don’t need to describe static assertions as their conditions are descriptive enough.

Different begin and end Types in Range-Based For Loop

Allows an end iterator to have a different type to the begin iterator, which is useful for implementing sentinels. Makes possible the implementation of C++20 ranges.