Oct 22, 2023 · If that invocation returns normally (such a call to std::call_once is known as returning), flag is flipped, and all other calls to std::call_once with the same flag are guaranteed to be passive. All active calls on the same flag form a single total order consisting of zero or more exceptional calls, followed by one returning call.

Feb 8, 2024 · invoke a free function: -9 invoke a lambda: 42 invoke a member function: 314160 invoke (i.e., access) a data member num_: 314159 invoke a function object: 18 invoke a lambda converting result to float: 33.000000 invoke print_num: 44

Dec 9, 2024 · Class template std::function is a general-purpose polymorphic function wrapper. Instances of std::function can store, copy, and invoke any CopyConstructible Callable target-- functions (via pointers thereto), lambda expressions, bind expressions, or other function objects, as well as pointers to member functions and pointers to data members.

Oct 16, 2021 · The class std::once_flag is a helper structure for std::call_once. An object of type std::once_flag that is passed to multiple calls to std::call_once allows those calls to coordinate with each other such that only one of the calls will actually run to completion. std::once_flag is neither copyable nor movable.

Oct 7, 2024 · std::function's allocator support was poorly specified and inconsistently implemented. Some implementations do not provide overloads at all, some provide the overloads but ignore the supplied allocator argument, and some provide the overloads and use the supplied allocator for construction but not when the std::function is reassigned. As a ...

Nov 25, 2024 · The named module std. compat exports the same declarations as the named module std, and additionally exports declarations in the global namespace corresponding to the declarations in namespace std that are provided by the C++ headers for C library facilities (e.g. ::fclose). For each declaration in the standard library,

Jan 7, 2022 · The completion of the function func synchronizes with all previous or subsequent calls to call_once with the same flag variable. 2) Complete object type capable of holding a flag used by call_once . 3) Expands to a value that can be used to initialize an object of type once_flag .

Mar 30, 2023 · Calls the host environment's command processor (e.g. /bin/sh, cmd.exe) with the parameter command.Returns an implementation-defined value (usually the value that the invoked program returns).

Dec 4, 2024 · std::bad_function_call is the type of the exception thrown by std::function::operator() if the function wrapper has no target.

Jun 5, 2024 · A call to the function signal() synchronizes-with any resulting invocation of the signal handler. If a signal handler is executed as a result of a call to std::raise (synchronously), then the execution of the handler is sequenced-after the invocation of std::raise and sequenced-before the return from it and runs on the same thread as std::raise.