interface ICoreWebView2SharedBuffer

Note

This reference is no longer being maintained. For the latest API reference, see WebView2 API Reference.

interface ICoreWebView2SharedBuffer
  : public IUnknown

The shared buffer object that is created by CreateSharedBuffer.

Summary

Members	Descriptions
Close	Release the backing shared memory.
get_Buffer	The memory address of the shared buffer.
get_FileMappingHandle	Returns a handle to the file mapping object that backs this shared buffer.
get_Size	The size of the shared buffer in bytes.
OpenStream	Get an IStream object that can be used to access the shared buffer.

The object is presented to script as ArrayBuffer when posted to script with PostSharedBufferToScript.

Applies to

Product	Introduced
WebView2 Win32	1.0.1661.34
WebView2 Win32 Prerelease	1.0.1671

Members

Close

Release the backing shared memory.

public HRESULT Close()

The application should call this API when no access to the buffer is needed any more, to ensure that the underlying resources are released timely even if the shared buffer object itself is not released due to some leaked reference. After the shared buffer is closed, the buffer address and file mapping handle previously obtained becomes invalid and cannot be used anymore. Accessing properties of the object will fail with RO_E_CLOSED. Operations like Read or Write on the IStream objects returned from OpenStream will fail with RO_E_CLOSED. PostSharedBufferToScript will also fail with RO_E_CLOSED.

The script code should call chrome.webview.releaseBuffer with the shared buffer as the parameter to release underlying resources as soon as it does not need access the shared buffer any more. When script tries to access the buffer after calling chrome.webview.releaseBuffer, JavaScript TypeError exception will be raised complaining about accessing a detached ArrayBuffer, the same exception when trying to access a transferred ArrayBuffer.

Closing the buffer object on native side doesn't impact access from Script and releasing the buffer from script doesn't impact access to the buffer from native side. The underlying shared memory will be released by the OS when both native and script side release the buffer.

get_Buffer

The memory address of the shared buffer.

public HRESULT get_Buffer(BYTE ** value)

get_FileMappingHandle

Returns a handle to the file mapping object that backs this shared buffer.

public HRESULT get_FileMappingHandle(HANDLE * value)

The returned handle is owned by the shared buffer object. You should not call CloseHandle on it. Normal app should use Buffer or OpenStream to get memory address or IStream object to access the buffer. For advanced scenarios, you could use file mapping APIs to obtain other views or duplicate this handle to another application process and create a view from the duplicated handle in that process to access the buffer from that separate process.

get_Size

The size of the shared buffer in bytes.

public HRESULT get_Size(UINT64 * value)

OpenStream

Get an IStream object that can be used to access the shared buffer.

public HRESULT OpenStream(IStream ** value)