TAL Programmer's Guide

Using Labels
Using Procedures
096254 Tandem Computers Incorporated 11–51
Using Undeclared Labels You need not declare labels before using them; however, if a variable and an
undeclared label in the same scope have the same identifier and if you use the label
before you access the variable, the compiler issues an error message.
No error results from the following example because the assignment to the variable
occurs before the label is used:
INT data;
PROC p;
BEGIN
INT a; !Declare local variable A
SUBPROC sp;
BEGIN
data := @a; !Assign address of local variable A
! because sublocal label A is not
! declared and not used yet
a: !Use sublocal label A
data := @a; !Assign address of sublocal label A
END;
CALL sp;
END;
Applying @ to a label name is not portable to future software platforms.