The newline declaration is deprecated. Programmers are strongly advised to use text-mode and binary-mode to individually specify whether streams or input files contain binary data or text. The declare #main-output and declare #main-input declarations are the recommended way to set the mode for main input and output.

The newline declaration changes the newline sequence for all data input or output by the program. As a side effect, it also causes all input and output to be performed in binary mode. If the programmer wishes to write text files in a program that has a newline declaration, the system-specific newline sequence must be written out explicitly. Such programs are less portable.

The newline declaration must appear before any rules in the program.

When the newline declaration is used in a program, the text-mode and binary-mode open modifiers are prohibited.

The default mode for all streams is text-mode unless the deprecated newline is used in the program.