Re: reference to variable fields in IBM copybooks

Scott Lindstrom wrote:

First - I reference these fields:

LIB-NAME OF QZDA-NDB-FORMAT2 (1)
LIB-NAME OF QZDA-NDB-FORMAT2 (2)
LIB-NAME OF QZDA-NDB-FORMAT2 (3)
LIB-NAME OF QZDA-NDB-FORMAT2 (4)
LIB-NAME OF QZDA-NDB-FORMAT2 (5)

This used to work but the copybook now is defined as:

05 NBR-OF-LIBRARIES PIC S9(00009) BINARY.
* Number of libraries in list
* 05 LIB-NAME PIC X(00010)
* OCCURS xxxxx TIMES.
* Varying number
* of library names

with LIB-NAME commented out. How can I readily access the first 'x' number
of occurrences of LIB-NAME (up to 5 of them) so I can move these fields to
the logfile record.

Scott:

This response needs to be short and quick, so I'll give the most basic answer that I know.

1. Create a simple 77- or 01-level My-Ptr POINTER data item in the WORKING-STORAGE Section.
2. Create a simple 01-level LIB-NAME pic X(10) item in the LINKAGE Section.
3. SET My-Ptr TO ADDRESS OF NBR-OF-LIBRARIES
4. SET My-Ptr UP BY LENGTH OF NBR-OF-LIBRARIES

At that moment, My-Ptr should be pointing to the first byte of whatever comes after NBR-OF-LIBRARIES.

5. SET ADDRESS OF LIB-NAME TO My-Ptr

At that moment, when you now reference LIB-NAME, you get the 10 bytes that follow NBR-OF-LIBRARIES in memory.

5. SET My-Ptr UP BY LENGTH OF LIB-NAME
6. SET ADDRESS OF LIB-NAME TO My-Ptr

You moved the pointer value 10 bytes further into memory; then you applied that new address to the Linkage definition. At that moment, when you now reference LIB-NAME, you get the 10 bytes that follow the previous LIB-NAME in memory.

Each time you increment the pointer by the length of the field and reassociate the new address, the definition moves forward. The incrementing will naturally be in a loop controlled by NBR-OF-LIBRARIES -- you can set the pointer beyond the memory described by NBR-OF-LIBRARIES, but you don't actually want to use any value of LIB-NAME from that address.

For the SQL-STATEMENT-TEXT, it's essentially the same. Make sure it's defined as varying length so that the LENGTH OF fits each new statement. (I can't recall if you need to add the 2-byte length or if it's handled.)

Hope that gets you going.

Tom Liotta