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Subroutines - Return Statements

DEFINE_FUNCTION also allows the use of the RETURN keyword that serves two purposes:

  1. To return prematurely from a function.
  2. To return a value from a function.

The format of the return statement is:

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RETURN [<return value>]

If a return statement is encountered anywhere in the function, execution of the function is terminated immediately and the value (if any) specified as the <return value> is returned to the caller.

A function that returns a value through the RETURN keyword must be declared with a return type. Conversely, a function that is declared without a return type cannot return a value. The return type may only be one of the 8 intrinsic data types. Strings, arrays, structures, classes and other user-defined types may not be returned.

When using DEFINE_FUNCTION with a return type CHAR, it is necessary to specify the length of the return value. For example:

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DEFINE_FUNCTION CHAR[2] GetBufferSize()

In the example below, GetBufferSize returns an unsigned 16-bit integer, BufSize. The return type is indicated before the DEFINE_FUNCTION keyword.

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DEFINE_FUNCTION INTEGER GetBufferSize()
LOCAL_VAR INTEGER BufSize = 0;
{
    .
    .
    .
    RETURN BufSize;
}

To call this function and to retrieve the RETURN value, use the following syntax:

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BufSize = GetBufferSize()

where BufSize is declared to be of type INTEGER.

Even if a function returns a value, it is not necessary to assign the return value to a variable. Both forms of the following call are valid:

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Count = ReadBuffer(Buffer,BufSize)
ReadBuffer(Buffer,BufSize) // return value is ignored

In the second case, the return value is simply thrown away.

See Also