Caché ObjectScript Reference
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Class Reference   

Contains information about the current terminal I/O device.
$ZIO contains information about the current I/O device.
For a terminal device that is a Terminal, $ZIO contains the string TRM:. If the current terminal device is connected remotely, $ZIO contains information about the remote connection.
For a terminal device connected through TELNET, $ZIO contains the following: host|port:
host The remote host IP address, in either IPv4 format:nnn.nnn.nnn.nnn, where nnn is a decimal number, or in IPv6 format: h:h:h:h:h:h:h:h, where h is a hexadecimal number. Further details on IPv4 and IPv6 formats can be found in the section Use of IPv6 Addressing in the chapter Server Configuration Options in the Caché Programming Orientation Guide.
port The remote IP port number.
These two values are separated by a vertical bar character. For example,|23. For further information, refer to the %Library.NetworkAddress class, a subclass of the data type class %Library.String.
If the current device is not a terminal:
The following example returns the current device information:
   SET x=$CASE($ZIO,"TRM:":"a terminal",
               "CON:":"a console",
               "":"neither terminal nor file")
   WRITE "The current device is ",x
This special variable cannot be modified using the SET command. Attempting to do so results in a <SYNTAX> error.
See Also