Kilowatt Software's
Classic Rexx Tutorial
Language Level 4.00 (TRL-2)

External data queue

The external data queue is a sequence of strings that are stored internally within the Rexx environment. All data queue interactions are simple line interactions. When Rexx passes control to commands, these commands may add lines to the external data queue, or extract lines from the data queue.

Rexx programs interact with the data queue with the following instructions.

When no lines remain in the data queue, the parse pull instruction reads a line from the default input stream instead.

The number of lines in the data queue can be determined by using the queued built-in function.

The following is an example of a program that uses data queue facilities.

Portability note: other Rexx implementations use the following additional data queue capabilities:

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Last updated on: 8 Aug 2002