Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide

BUFSIZE

The BUFSIZE option specifies the number of bytes for a buffer.

Read syntax diagramSkip visual syntax diagram>>-BUFSIZE--(n)------------------------------------------------><
 

RECORD output is buffered by default and has a default value for BUFSIZE of 64k. STREAM output is buffered, but not by default, and has a default value for BUFSIZE of zero.

If the value of zero is given to BUFSIZE, the number of bytes for buffering is equal to the value specified in the RECSIZE or LRECL option.

The BUFSIZE option is valid only for a consecutive binary file. If the file is used for terminal input, you should assign the value of zero to BUFSIZE for increased efficiency.

Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide