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winrt::capture function template (C++/WinRT)

  • Article

A function template that calls a specified function or method (automatically calling winrt::check_hresult on it), captures the interface pointer that's output from the function or method, and returns it as the template parameter typename T if T derives from Windows::Foundation::IUnknown, otherwise, returns a winrt::com_ptr. Throws if not successful.

Also see the winrt::com_ptr::capture function.

Syntax

template <typename T, typename F, typename...Args>
impl::com_ref<T> capture(F function, Args&& ...args);

template <typename T, typename O, typename M, typename...Args>
impl::com_ref<T> capture(O* p, M method, Args&& ...args);

template <typename T, typename O, typename M, typename...Args>
impl::com_ref<T> capture(com_ptr<O> const& object, M method, Args&& ...args);

Template parameters

typename T The type of the interface pointer that's output from the function or method.

typename F A function object type, such as a free function, or std::function.

typename O An interface type.

typename M A method type.

typename Args Zero or more argument types.

Parameters

function A function object of type F.

p A pointer to an object of type O.

object A winrt::com_ptr of type O.

method A method (implemented by O) of type M.

args Zero or more arguments of type Args.

Return value

Returns T if T derives from Windows::Foundation::IUnknown, otherwise, returns winrt::com_ptr. Throws if not successful.

Remarks

  • The capture(F function, Args&&...args) overload invokes the function object.
  • The capture(O* p, M method, Args&& ...args) overload invokes the method on the pointer.
  • The capture(winrt::com_ptr<O> const& object, M method, Args&&...args) overload invokes the method on the object.

All overloads pass through (to the invokee) any additional arguments that you provide. All overloads also pass the two additional arguments that such invokees require—specifically, a REFIID (the ID of the target of the winrt::com_ptr), and a void** (The address of a pointer to the target of the winrt::com_ptr).

Requirements

Minimum supported SDK: Windows SDK version 10.0.17134.0 (Windows 10, version 1803)

Namespace: winrt

Header: %WindowsSdkDir%Include<WindowsTargetPlatformVersion>\cppwinrt\winrt\base.h (included by default)

See also