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std::inout_ptr - cppreference.com

From cppreference.com

template< class Pointer = void, class Smart, class... Args > auto inout_ptr( Smart& s, Args&&... args );

 (since C++23)

Returns an inout_ptr_t with deduced template arguments that captures arguments for resetting by reference.

The program is ill-formed if construction of the return value (see below) is ill-formed.

Parameters

s - the object (typically a smart pointer) to adapt
args... - the arguments for resetting to capture

Return value

std::inout_ptr_t<Smart, P, Args&&>(s, std::forward<Args>(args)...), where P is

  • Pointer, if Pointer is not same as void, otherwise,
  • Smart::pointer, if it is valid and denotes a type, otherwise,
  • Smart::element_type*, if Smart::element_type is valid and denotes a type, otherwise,
  • std::pointer_traits<Smart>::element_type*.

Notes

Users may specify the template argument for the template parameter Pointer, in order to interoperate with foreign functions that take a Pointer*.

As all arguments for resetting are captured by reference, the returned inout_ptr_t should be a temporary object destroyed at the end of the full-expression containing the call to the foreign function, in order to avoid dangling references.

Feature-test macro Value Std Feature
__cpp_lib_out_ptr 202106L (C++23) std::out_ptr, std::inout_ptr
202311L (C++26) freestanding std::out_ptr and std::inout_ptr

Example

See also