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

SOSI

This option specifies how source containing the DBCS shift-out and shift-in characters is handled.

Read syntax diagramSkip visual syntax diagram   .-NOSOSI-.
>>-+-SOSI---+--------------------------------------------------><
 
NOSOSI
Under the NOSOSI option, there will be no special handling of these characters.
SOSI
Under the SOSI option, the compiler will accept and correctly process source containing the DBCS shift-out and shift-in characters.
Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide