If the specified delimiter contains any special characters, enclose
it in apostrophes. In this case, a special character is any character
that is neither alphanumeric nor national ($, #, @).
Failing to
code enclosing apostrophes produces unpredictable results.
If the delimiter contains an ampersand or an apostrophe, code
each ampersand or apostrophe as two consecutive ampersands or apostrophes.
Each pair of consecutive ampersands or apostrophes counts as one
character.
The DLM parameter can have a null value only when coded on a DD
which either: