If the DBCS assembler option is specified, then the following additional rules apply:

• Because ampersand is not recognized in double-byte data, variable symbols must not be present in double-byte data.
• The concatenation character is mandatory when double-byte data is to follow a variable symbol.
• The assembler checks for redundant SI and SO at concatenation points. If the byte to the left of the join is SI and the byte to the right of the join is SO, then the SI/SO pair is considered redundant and is removed.
  Note: The rules for redundant SI and SO are different for variable substitution and listing display, which are described at Listing of generated fields containing double-byte data.

The following example shows these rules:

&SYMBOL  SETC            '<DcDd>'
DBCS     DC              C'<DaDb>&SYMBOL.<.&.S.Y.M.B.O.L>'

The SI/SO pairs between double-byte characters Db and Dc, and Dd and .&, are removed. The variable symbol &SYMBOL is recognized between the double-byte strings but not in the double-byte strings. The result after concatenation is:

DBCS     DC              C'<DaDbDcDd.&.S.Y.M.B.O.L>'