An MHP executing continuous-inquiry-response processing calls the function dc_mcf_receive(), then receives a message from the terminal. After terminating processing, the MHP returns a response with the function dc_mcf_reply(). To switch to an MHP for continuous processing when a response is returned, specify the application name of the new MHP in the function dc_mcf_reply(). Without the application name specified, the previous MHP is started.

Also, the MHP, handling continuous-inquiry-response processing, can start an application by using the function dc_mcf_execap(). Only immediate start is permitted. In this case, only one MHP with cont specified can be started by executing the function dc_mcf_execap(). The MHP that started the application with cont specified cannot use the function dc_mcf_reply() because the continuous response right has moved from the MHP. Also, the MHP cannot use the function dc_mcf_contend().

The function dc_mcf_send() (a send-only message to a terminal) can be used even during continuous-inquiry-response processing.

Temporary-stored data can be used during continuous inquiry-response processing. The temporary-stored data is used as information for transferring processing to the subsequent MHP to be started. Temporary-stored data can be used at a logical terminal. Thus, continuous-inquiry-response processing can be carried out by using one MHP shared by multiple logical terminals.

Allocate an update area and a recovery area as temporary-stored data areas in the shared memory. For each MHP, specify the length of the temporary-stored data storage area in the MCF application definition.

Temporary-stored data can be used only when the continuous-inquiry-response mode is enabled. Temporary-stored data cannot be used in other message communication modes.

(a) Receiving temporary-stored data

Call the function dc_mcf_tempget() [CBLDCMCF('TEMPGET')] to use temporary-stored data from an MHP. The function dc_mcf_tempget() is executed on the assumption that there is (00)₁₆ of the length specified in tempsize of the MCF application attribute definition in the following cases:

• The temporary-stored data storage area is in initial state.
• There is no temporary-stored data.

If the receive area length specified in the function dc_mcf_tempget() is shorter than the length of temporary-stored data, only the portion of temporary-stored data equivalent to the specified length is received. The excess portion is truncated. If the receive area length specified in the function dc_mcf_tempget() is larger than the temporary-stored data length, only the temporary-stored data is stored in the receive area.

(b) Updating temporary-stored data

To update temporary-stored data, use the function dc_mcf_tempput() [CBLDCMCF('TEMPPUT')]. When the temporary-stored data, area for storing is updated, the data itself is replaced. A value exceeding the value specified in the MCF application definition cannot be set as the length of update area.

Call the function dc_mcf_tempget() before the function dc_mcf_tempput(). Otherwise, the dc_mcf_tempput() returns with an error.

Continuous-inquiry-response processing terminates when one of the events shown below is executed. The temporary-stored data storage area which has been used is deleted when continuous-inquiry-response processing terminates.

• The function dc_mcf_contend() [CBLDCMCF('CONTEND ')] is called from the MHP.
• The logical terminal name is specified in the mcftendct command in order to forcibly terminate continuous-inquiry-response processing.
  The mcftendct command can also be called by using the function dc_adm_call_command() from a UAP which is not involved in continuous-inquiry-response processing.
  
• The UAP terminates abnormally.
  The UAP terminates abnormally if the MHP that executed continuous-inquiry-response processing does not use the function dc_mcf_reply().
  

If the UAP terminates abnormally during continuous-inquiry-response processing, ERREVT3 is reported. The continuous-inquiry-response processing can be continued by the following:

• Use the MCF event handling MHP corresponding to this ERREVT3 in order to use the function dc_mcf_reply() in which the name of the next application to be started is specified. The continuous-inquiry-response processing terminates if the function dc_mcf_reply() is not called.

The figure below shows continuous-inquiry-response processing.

Figure 3-11 Outline of continuous-inquiry-response processing