Using TestN for validating positive numbers

 
C                   MOVEL     '12G'         SIN               3
C                   MOVE      *zeros        WORK              4
C                   MOVEL     SIN           WORK
C                   TESTN                   WORK                  81
c                   eval       *inlr = *on

By putting that extra zero at the end, the "G" ends up in the middle of the number, and will signal an error.

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