pTAL Conversion Guide

Statements

pTAL Conversion Guide—527302-002

15-19

RETURN Statement

A RETURN statement causes a routine to return control to its caller. When you return

from a function, the RETURN statement also specifies a value to return to the

function’s caller.

Topics:

•

RETURN Statement on page 15-19

•

Returning a Value and Condition Code in TAL on page 15-20

•

Returning a Condition Code in pTAL on page 15-20

RETURN Statement

TAL

A RETURN statement is not required in a function body. The TAL compiler reports a

warning if a function does not have a RETURN statement, but it continues compiling

and produces executable code if it does not detect errors. The function returns 0 to its

caller when it reaches the end of its code.

pTAL

Every function must include at least one RETURN statement, although the native

compiler does not verify that every path through a function’s code includes a RETURN

statement; therefore, a function can reach the end of its code, in which case the

program traps with an Invalid Instruction run-time error. If pTAL generates the code for

Example 15-25 on page 15-19 and i is greater than or equal to 0, the program traps

upon reaching the END at the end of p’s code.

Note. In the discussion of the RETURN statement, the word “procedure” implies both

procedures and subprocedures but not functions.

Example 15-25. RETURN Statement

INT PROC p(i);

INT i;

BEGIN

IF i < 0 THEN RETURN 1; ! Return 1 if i < 0

END; ! Otherwise, return 0