Asynchronous Terminals and Printer Processes Programming Manual

TERMINAL I/O

Break Characteristics

The file system permits a terminal operator to signal a process

| by pressing the BREAK key while operating in conversational mode

| or block mode. For example, a terminal operator can press the

| BREAK key while an application is running through the command

| interpreter. However, the effect of the BREAK key while the

| application is running through the command interpreter depends on

| whether the application performs its own break handling. If the

| application does not perform its own break handling, pressing the

| BREAK key returns the command interpreter to command input mode.

| If the application performs its own break handling, pressing

| the BREAK key interrupts the application without requiring

| the application to periodically check the terminal for input.

| However, the application must check the $RECEIVE file for a BREAK

| message.

Table 2-2 summarizes the characteristics that control break

checking.

Table 2-2. Break Characteristics

SYSGEN SETMODE SETPARAM CMI

Characteristic Modifier Parameter Parameter Attribute

_______________________________________________________________

Enable/disable NOBREAKMON* 11 (none) BRKENABLE

break checking

Transfer count BREAKCOUNT (none) (none) BRKCOUNT

in system status

Echo break ECHOBREAK** (none) (none) (none)

Set access mode (none) 12 (none) (none)

Set/fetch BREAK- (none) (none) 3 (none)

handling param-

meters

_______________________________________________________________

* For TERMPROCESS subdevices only

** For 6520 and 6530 terminals supported by ATP6100 only

2-4 November 1987