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Windows Driver Kit DDI reference (nc-vmbuskernelmodeclientlibapi-fn_vmb_channel_save_continue)

FN_VMB_CHANNEL_SAVE_CONTINUE callback function

Description

[Some information relates to pre-released product which may be substantially modified before it's commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here.]

The VmbChannelSaveContinue function saves the channel state to a buffer. Run the VmbChannelSaveBegin before you run this function. The driver must check the return value of the function.

Parameters

`Channel`

A handle for a channel to save.

`SaveBuffer`

A pointer to the buffer into which to save state information.

`SaveBufferSize`

The size, in bytes, of the save buffer.

`BytesFilled`

A pointer to a variable that receives the number of bytes that were copied to the save buffer.

`BytesRequired`

A pointer to a variable that receives the number of bytes that are needed for this function to make progress on the next call.

Return value

VmbChannelSaveContinue returns the following values:

Return code	Description
STATUS_SUCCESS	The state was saved.
STATUS_BUFFER_TOO_SMALL	The save buffer was too small. The BytesNeeded parameter contains the number of bytes that are required to make any progress.
STATUS_STATUS_BUFFER_OVERFLOW	Some data was written to the save buffer, but there is more data to be saved.

Prototype

//Declaration

FN_VMB_CHANNEL_SAVE_CONTINUE FnVmbChannelSaveContinue;

// Definition

NTSTATUS FnVmbChannelSaveContinue
(
    VMBCHANNEL Channel
    PVOID SaveBuffer
    ULONG SaveBufferSize
    PULONG BytesFilled
    PULONG BytesRequired
)
{...}

Remarks

The save process saves the data in "chunks" and can continue from the point it stopped.

If the caller did not allocate enough space in advance, multiple calls may be needed.

[!IMPORTANT] This function is called through the VMBus Kernel Mode Client Library (KMCL) interface, provided by the Vmbkmcl.sys bus driver. This is a server-only function accessed from the KMCL_SERVER_ONLY_METHODS structure.

For more information, see the Remarks section of KMCL_SERVER_ONLY_METHODS.

FN_VMB_CHANNEL_SAVE_CONTINUE - NtDoc