Microsoft SQL Server Virtual Backup Device Specification
IServerVirtualDevice::SendCommand
| Purpose | This function sends a command to the client by using a virtual device object returned from IServerVirtualDeviceSet2::OpenDevice. | |
| Syntax | HRESULT IServerVirtualDevice::SendCommand (
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| Parameters | Argument | Explanation |
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| pCmd | This is a pointer to a command request block. For more information, see Commands. The completionFunction field must be set to point to the address of a function with the following signature:
void callbackFunction ( VDS_Command *pCmd); This callback is made by the completion agent when the client indicates that a command has been completed. SQL Server sets the completionContext field of the pCmd. Its purpose is to provide context to the callback function. |
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| Return Values | Argument | Explanation |
| NOERROR | The command is successfully queued to the client. | |
| VD_E_QUEUE_FULL | The device queue is full. | |
| VD_E_IO_ERROR | The device is in an IO-ERROR state. | |
| VD_E_PROTOCOL | The device is not active. | |
| Remarks | When an error occurs while attempting to send the command, the callback function is invoked, and the completionCode in the command buffer is set as follows:
For more information, see Command Error Handling. |
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