The first assignment statement uses the F$MESSAGE function to return
the message that corresponds to the hexadecimal value 1C. The message
is returned as a character string and is assigned to the symbol MESSAGE.
The F$LENGTH function is then used to return the length of the
character string assigned to the symbol MESSAGE. You do not need to use
quotation marks (" ") when you use the symbol MESSAGE as an
argument for the F$LENGTH function. (Quotation marks are not used
around symbols in character string expressions.)
The F$LENGTH function returns the length of the character string and
assigns it to the symbol STRING_LENGTH. At the end of the example, the
symbol STRING_LENGTH has a value equal to the number of characters in
the value of the symbol named MESSAGE, that is, 33.