IHostIoCompletionManager::GetHostOverlappedSize Method

Gets the size of any custom data the host intends to append to I/O requests.

HRESULT GetHostOverlappedSize (
    [out] DWORD *pcbSize
);

Parameters

• pcbSize
  [out] A pointer to the number of bytes that the common language runtime (CLR) should allocate in addition to the size of the Win32 OVERLAPPED object.

Return Value

HRESULT	Description
S_OK	GetHostOverlappedSize returned successfully.
HOST_E_CLRNOTAVAILABLE	The CLR has not been loaded into a process, or the CLR is in a state in which it cannot run managed code or process the call successfully.
HOST_E_TIMEOUT	The call timed out.
HOST_E_NOT_OWNER	The caller does not own the lock.
HOST_E_ABANDONED	An event was canceled while a blocked thread or fiber was waiting on it.
E_FAIL	An unknown catastrophic failure occurred. When a method returns E_FAIL, the CLR is no longer usable within the process. Subsequent calls to hosting methods return HOST_E_CLRNOTAVAILABLE.

Remarks

All asynchronous I/O calls to Windows Platform APIs take a Win32 OVERLAPPED object, which provides information such as the file pointer position. To maintain state, applications that make asynchronous I/O calls typically add custom data to the structure. GetHostOverlappedSize and IHostIoCompletionManager::InitializeHostOverlapped provide an opportunity for the host to include such custom data.

The CLR calls the GetHostOverlappedSize method to determine the size of the custom data that the host intends to append to the OVERLAPPED object.

Note:
GetHostOverlappedSize is called only once. The host's custom data must be the same size for every I/O request.

Important Note:
The size of the OVERLAPPED object itself is not included in the value of pcbSize.

For more information about the OVERLAPPED structure, see the Windows Platform documentation.

Requirements

Platforms: Windows 2000, Windows XP, Windows Server 2003 family

Header: MSCorEE.idl

Library: Included as a resource in MSCorEE.dll

.NET Framework Version: 2.0

See Also

Concepts

ICLRIoCompletionManager Interface

IHostIoCompletionManager Interface

Reference

NativeOverlapped