Preserving double ampersands

You can use the &NRSTR built-in function to prevent a CLIST from:

Removing the first ampersand when it encounters a character string with a prefix of double ampersands.
Performing more than one level of symbolic substitution on a variable.

You can use &NRSTR with JCL statements that include the name of a temporary data set (for example, &&TEMP). Using &NRSTR prevents a CLIST from changing the name of a temporary data set (&&TEMP) to a symbolic parameter (&TEMP).