System Parameters

Description

The 'XC' parameter sets PxPlus to ignore write errors to the connected terminal. This allows a process to continue running and outputting to a terminal, even while the terminal is no longer connected. The process should continue until a READ/INPUT request, then the error is reported and PxPlus terminates.

This parameter should be used when there is the possibility that a terminal could become disconnected during an update process, and it is important to the application that the application complete its processing before having to handle the disconnect.

When the 'XC' parameter is enabled, terminal disconnects (channel 0) are not immediately reported to the application program. This allows a process to trap the disconnect condition and handle it properly.

Normally (when 'XC' is not enabled), a terminal disconnect will cause the system to complete processing the current instruction and shut down. No application recovery of this condition is possible.

When 'XC' is enabled, the system will continue to run; however, all output requests to the terminal will be ignored with no error reported, and all input requests will be returned with an Error #86. In addition, most update processes will be able to complete their processing without having to worry about a premature termination caused by a disconnect.

Important Note:
When running WindX, some file IO functions and variables processed against channel 0 cause an exchange of information with the WindX terminal. These functions will generate an Error #86 should the terminal have disconnected while 'XC' is enabled. The most commonly used functions that are affected are FIB, FIN, TXW, TXH and MSE.

Default

Off - The system generates the error and terminates the process.