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As of the 2011 revision, the C++ language also supports closures, which are a type of function object constructed automatically from a special language construct called lambda-expression. A C++ closure may capture its context either by storing copies of the accessed variables as members of the closure object or by reference.
C++11 allowed lambda functions to deduce the return type based on the type of the expression given to the return statement. C++14 provides this ability to all functions. It also extends these facilities to lambda functions, allowing return type deduction for functions that are not of the form return expression;.
C++17 is a version of the ISO/IEC 14882 standard for the C++ programming language. C++17 replaced the prior version of the C++ standard, called C++14 , and was later replaced by C++20 . History
Blocks are a non-standard extension added by Apple Inc. to Clang's implementations of the C, C++, and Objective-C programming languages that uses a lambda expression-like syntax to create closures within these languages.
C++ C++11 closures can capture non-local variables by copy construction, by reference (without extending their lifetime), or by move construction (the variable lives as long as the closure does). The first option is safe if the closure is returned but requires a copy and cannot be used to modify the original variable (which might not exist any ...
Calling f with a regular function argument first applies this function to the value 2, then returns 3. However, when f is passed to call/cc (as in the last line of the example), applying the parameter (the continuation) to 2 forces execution of the program to jump to the point where call/cc was called, and causes call/cc to return the value 2.
In C++ computer programming, copy elision refers to a compiler optimization technique that eliminates unnecessary copying of objects.. The C++ language standard generally allows implementations to perform any optimization, provided the resulting program's observable behavior is the same as if, i.e. pretending, the program were executed exactly as mandated by the standard.
The term variable capture is somewhat misleading, because all namespaces are vulnerable to unwanted capture, including the operator and function namespace, the tagbody label namespace, catch tag, condition handler and restart namespaces. Variable capture can introduce software defects. This happens in one of the following two ways: