Library  Semaphores, efficient atomic waiting, latches, and barriers  std::atomic_ref  Designated Initializers  Spaceship Operator <=>  Range-based for Loop Initializer  Non-Type Template Parameters while std::atomic always copies the value it is providedMany More New Features…47 Designated Initializers  Designated initialization of aggregates  E.g.: struct Data { int anInt { 0 }; std::string <=>  vector, string, map, set, sub_match, …  Example:53 Range-based for Loop Initializer  Initializers for switch statements (C++17): struct Foo { int value; int result; }; Foo GetData() { return

calls through utilizing combination of : ▪POD structs -- structs with data members only ▪designated initializers -- initializing a struct with: { .field = value } ▪structured binding -- disaggregating no room for accidentally switching the road state -- There is only one. // the .= syntax is a designated initializer used to assign POD values auto result = processCarStateTransition({ .car = Car::FastSportsCar

}Limitations of struct u No static reflection u No static generation u No required members u Designated initializers required to be in order (in C++ not C)No static reflection u Although there is a way to

Arguments • A recurring request • Prior efforts exist, e.g.: N4172 • There are workarounds with designated initializers 140P2966 requests: miscellaneous • SoA to AoS • Arrays of structs (AoS) make it easier

could use in-class member initializers. struct Widget { Widget() {} Widget( int j ) : i {j} // Initializing to j {} // Data members with in-class initializers int i{42}; initializing to "CppCon" int* pi{}; // initialising to nullptr }; In-class member initializers are used if the data member is not explicitly listed in the member initializer list.Data Member Widget( int j ) : i {j} // Initializing to j {} // Data members with in-class initializers int i{42}; // initializing to 42 std::string s{"CppCon"}; // initializing

9 用Tcommunication C++14: Lambda Capture Initializers *， Since C++14, you can pass initializers to lambda captures - Enables adding local state - Enables capturing by const

to the basic character set @, $, and ` 21gcc 14 impl example P2752 Static storage for braced initializers std::vector v = {1,2,3}; //what does this do? 1 2 std::vector vimg = { 3 }; 5 https://godbolt.org/z/havqf5cPT 22gcc 14 impl example P2752 Static storage for braced initializers std::vector v = {1,2,3}; //what does this do? 1 2 std::vector vimg = { 3

arg) { new(&mbuf->value) std::int32_t(arg); } }; Stroustrup - "Primitive" - CppCon 2020 31 initializers Read/write access Field names Typed buffer for the Flat Allocator for the message tail Place

put(int c); // write c to standard output int put(int c, FILE *f); // write c to a designated file *f  Even though they use intas a parameter type, you can pass them a charas the argument put(int c); // write c to standard output int put(int c, FILE *f); // write c to a designated file *f  You could declare it as a single function with a default argument for the second parameter:

capacity: 16 allocation: size: 10 capacity: 16“…a sentinel node is a specifically designated node used with linked lists and trees as a traversal path terminator. This type of node does