SMB Routines, SMB$SEND_TO_JOBCTL, Description
*Conan The Librarian
The symbiont uses the SMB$SEND_TO_JOBCTL routine to send messages to the job controller. Most messages the symbiont sends to the job controller are responses to requests made by the job controller. These responses inform the job controller that the request has been completed, either successfully or with an error. When the symbiont sends the message, it usually indicates that the request has been completed. In such messages, the request argument corresponds to the function code of the request that has been completed. Thus, if the job controller sends a request using the SMBMSG$K_START_ TASK code, the symbiont responds by sending a SMB$SEND_TO_JOBCTL message using SMBMSG$K_START_TASK as the request argument. The responses to some requests use additional arguments to send more information in addition to the request code. The following table shows which additional arguments are allowed in response to each different request: Request Arguments SMBMSG$K_START_STREAM request device_status error SMBMSG$K_STOP_STREAM request SMBMSG$K_RESET_STREAM request SMBMSG$K_START_TASK request SMBMSG$K_PAUSE_TASK request SMBMSG$K_RESUME_TASK request SMBMSG$K_STOP_TASK request error (See footnote.) Footnote: This is usually the value specified in the SMBMSG$K_ STOP_CONDITION item that was sent by the job controller with the SMBMSG$K_STOP_TASK request.) In addition to responding to requests from the job controller, the symbiont can send other messages to the job controller. If the symbiont sends a message that is not a response to a request, it uses either the SMBMSG$K_TASK_COMPLETE or SMBMSG$K_TASK_STATUS code. Following are the additional arguments that you can use with the messages identified by these codes: Code Arguments SMBMSG$K_TASK_ request COMPLETE accounting error SMBMSG$K_TASK_STATUS request checkpoint device_status The symbiont uses the SMBMSG$K_TASK_STATUS message to update the job controller on the status of a task during the processing of that task. The checkpoint information passed to the job controller with this message permits the job controller to restart an interrupted task from an appropriate point. The device-status information permits the symbiont to report changes in device's status (device stalled, for example). The symbiont can use the SMBMSG$K_TASK_STATUS message to request that the job controller send a stop-stream request. It does this by setting the stop-stream bit in the device-status argument. The symbiont can also use the SMBMSG$K_TASK_STATUS message to notify the job controller that the symbiont has paused in processing a task. It does so by setting the pause-task bit in the device-status argument. The symbiont uses the SMBMSG$K_TASK_COMPLETE message to signal the completion of a task. Note that, when the symbiont receives a START_TASK request, it responds by sending a SMB$SEND_TO_JOBCTL message with SMBSMG$K_START_TASK as the request argument. This response means that the symbiont has started the task; it does not mean the task has been completed. When the symbiont has completed a task, it sends a SMB$SEND_TO_JOBCTL message with SMBMSG$K_TASK_COMPLETE as the request argument. Optionally, the symbiont can specify accounting information when sending a task-completion message. The accounting statistics accumulate to give a total for the job when the job is completed. Also, if the symbiont is aborting the task because of a symbiont- detected error, you can specify up to three condition values in the error argument. Aborting a task causes the remainder of the job to be aborted.