Some correct examples of VC_USING commands follow.
Example 1: Accumulate real fields TOT01 -> TOT05 into virtual field TOTAL:
C*
C* VC_USING FIELDS(TOT01 TOT02 TOT03 TOT04 TOT05 TOTAL)
C*
C Z-ADDTOT01 TOTAL
C ADD TOT02 TOTAL
C ADD TOT03 TOTAL
C ADD TOT04 TOTAL
C ADD TOT05 TOTAL
Some points to note about this example are:
- The VC_USING command details all fields in the code section that come from the file definition. The command is included into the source code as a comment so as not to upset the RPG syntax checker when editing and begins in column 9.
- None of the fields are declared (i.e. type and length specified). LANSA automatically declares all real and virtual file fields in a data structure.
If this example virtual field code section was actually compiled into the file I/O module it would look something like this:
* FIELD REPLACEMENT VALUES USED FOR THIS SECTION OF USER CODE
*
* Field name as Field name as in Internal field name
*in file definition user RPG code used as replacement
*------------------ ---------------- ------------------
* TOT01 TOT01 @F0001
* TOT02 TOT02 @F0002
* TOT03 TOT03 @F0003
* TOT04 TOT04 @F0004
* TOT05 TOT05 @F0005
* TOTAL TOTAL @F0006
*
C Z-ADD@F0001 @F0006
C ADD @F0002 @F0006
C ADD @F0003 @F0006
C ADD @F0004 @F0006
C ADD @F0005 @F0006
Note how the VC_USING command has been replaced by a series of comments that detail exactly what effect it has on the following code. Also, note how all fields listed in the VC_USING command have been replaced by their "internal" names in the actual code section.
Example 2: Accumulate real fields TOT01 -> TOT05 into virtual field FULLTOTAL:
C*
C* VC_USING FIELDS(TOT01 TOT02 TOT03
C* TOT04 TOT05 (FULLTOTAL FFFFFF))
C*
C Z-ADDTOT01 FFFFFF
C ADD TOT02 FFFFFF
C ADD TOT03 FFFFFF
C ADD TOT04 FFFFFF
C ADD TOT05 FFFFFF
Some points to note about this example are:
- The VC_USING command has been continued over 2 source lines by use of the "+" continuation character. In addition, it indicates that file field "FULLTOTAL" is actually referenced by name "FFFFFF" in the following code. This was done because field name FULLTOTAL is more than 6 characters long.
- The name FFFFFF has been used in place of name FULLTOTAL in all RPG code lines.
If this example virtual field code section was actually compiled into the file I/O module it would look something like this:
FIELD REPLACEMENT VALUES USED FOR THIS SECTION OF USER CODE
*
* Field name as Field name as in Internal field name
*in file definition user RPG code used as replacement
*------------------ ---------------- -------------------
* TOT01 TOT01 @F0001
* TOT02 TOT02 @F0002
* TOT03 TOT03 @F0003
* TOT04 TOT04 @F0004
* TOT05 TOT05 @F0005
* FULLTOTAL FFFFFF @F0006
*
C Z-ADD@F0001 @F0006
C ADD @F0002 @F0006
C ADD @F0003 @F0006
C ADD @F0004 @F0006
C ADD @F0005 @F0006
Again the VC_USING command has been replaced by a series of comments that detail exactly what effect it has had on the following code. Also note how all fields listed in the VC_USING command have been replaced by their "internal" names, particularly the name "FFFFFF".