TAL Reference Manual

Standard Functions

TAL Reference Manual—526371-001

14-36

Example of $OVERFLOW Function

This example turns overflow trapping off, tests the overflow indicator, and turns

overflow trapping back on. CODE statements, however, are not portable to future

software platforms; modularize their use where possible:

INT i, j, k;

CODE (RDE;

ANRI $COMP (%200); !Turn off overflow trap bit

SETE);

i := j + k;

IF $OVERFLOW THEN i := 0; !Test overflow indicator

CODE (RDE;

ANRI $COMP (%040); !Turn on overflow trap bit

ORRI %200; !Disable pending overflow

SETE);

$PARAM Function

The $PARAM function checks for the presence or absence of an actual parameter in

the call that invoked the current procedure or subprocedure.

formal-param

is the identifier of a formal parameter as specified in the procedure or subprocedure

declaration.

Usage Considerations

If the actual parameter corresponding to formal-param is present in the CALL

statement, $PARAM returns 1. If the actual parameter is absent from the CALL

statement, $PARAM returns 0.

Only a VARIABLE procedure or subprocedure or an EXTENSIBLE procedure can use

$PARAM. If such a procedure or subprocedure has required parameters, it must check

for the presence or absence of each required parameter in CALL statements. The

procedure or subprocedure can also use $PARAM to check for optional parameters.

$PARAM ( formal-param

)

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