ASCII Printer and Plotter Exit Processing
The ASCII and TCPASCII link drivers use the ASCII printer and plotter exits to build device-specific data streams for transmission to a printer or plotter. With ASCII-type links, the ASCII printers or plotters are connected to RSCS by an IBM 3171 controller. TCPASCII-type links communicate with ASCII printers or plotters that are attached to a terminal server in a TCP/IP network.
ASCII printer and plotter exit routines are called at seven points in the ASCII and TCPASCII link drivers' operational cycle. Each exit routine contains entry points, which provide the following additional processing for each of the seven calls.
| Entry Point | Function |
|---|---|
| Initialization | Called when the link driver is being initialized. |
| TAG Processing | Called when the link driver opens a new spool file. |
| Record Processing | Called when a record is read from the input spool file. |
| Device Reset | Called when a file ends or is flushed, backspaced, or forward-spaced. |
| Message Processing | Called when a message is received for output to the printer or plotter. |
| Attention Interrupt Processing | Called when the controller device generates an attention interrupt. |
| Termination | Called when the link driver is terminating. |
The message, attention interrupt, and termination processing routines, are not necessary to support an ASCII or TCPASCII link driver; you do not have to supply these routines.
The termination routine is not necessary to support an ASCII or TCPASCII link driver; you do not have to supply this routine. An exit may require the termination routine for potential clean up processing such as returning any storage obtained in any of the other six exit routines.
The order in which the exit routines are listed above are not necessarily the order in which the ASCII or TCPASCII link driver will call them when processing a print stream.
The exit routine module that contains the exit routines to be used for a specific ASCII-type or TCPASCII-type link must be identified on the PARM configuration statement for the link or in the link operational parameters on the RSCS DEFINE or START command. For more information, see z/VM: RSCS Networking Planning and Configuration and z/VM: RSCS Networking Operation and Use.