pTAL Reference Manual (H06.03+)

Procedures, Subprocedures, and Procedure

Pointers

HP pTAL Reference Manual—523746-005

14-37

Labels in Procedures

A label is the target location of a GOTO statement.

identifier

is as described in Identifiers on page 2-8. It cannot be an entry-point identifier.

The following guidelines apply:

•

LABEL is not a valid data type for a formal procedure parameter. You cannot pass

a label to a procedure.

•

A label is not a valid actual procedure parameter.

•

If a GOTO statement in a subprocedure branches to a label in the containing

procedure, the label must be declared in a LABEL declaration in the containing

procedure, before the subprocedure that contains the GOTO statement (see

Nonlocal on page 12-24).

•

The executable statement identified by a label cannot be an IF statement that tests

the hardware indicator.

The conditional expression in an IF statement that is identified by a label cannot test a

hardware indicator.

Note. This is not recommended in pTAL because it is very inefficient.

Example 14-21. IF Statements Identified by Labels

INT i, j := 0;

i := i + 1;

IF < THEN ... ! OK

i := i + 1

label_a:

IF < THEN ... ! ERROR: label cannot immediately precede an

! IF statement that tests a hardware indicator

;

VST196.vsd

identifierLABEL