MOVE statement

mlp · New User Joined: 23 Sep 2005 Posts: 91

There is a scenario which I am facing currently as mentioned below.

01 XYZ PIC X(2000).
01 PQR PIC X(2001).

The PQR has some data and in the last byte of PQR there is character 'V' stored and then we issue move statement as below.

MOVE XYZ TO PQR

After this the 2001th byte of PQR which has character 'V' becomes space.

I checked many times in the code but could not figure out the reason.

As per my knowledge the last character should have been retained.

Can anybody justify this behaviour?

enrico-sorichetti · Posted: Thu Dec 02, 2010 12:20 pm

but as per cobol knowledge ( and the <majority> of other languages )

char moving
from smaller to larger clears/fills the <excess> trailing <space> with blanks
from larger to smaller ( if allowed ) truncates the excess ( trailing side )

numeric moving
from smaller to larger clears/fills the <excess> leading <space> with zeroes
from larger to smaller ( if allowed ) truncates the excess (leading side )

that' s what is GENERALLY safe to assume

to retain <some> values in the destination use a <substringing> approach,
==>for cobol the reference modification

mlp · New User Joined: 23 Sep 2005 Posts: 91

I tried with a sample program and found out that whatever you are saying is correct.

My wrong presumption led me to post this topic. So learning is, dont presume without verification !!

It is always better to be enlightened.....

jerryte · Posted: Tue Dec 07, 2010 1:44 am

The below is from the COBOL Reference guide. This is under the heading "Alignment Rules" in the Data Division Overview chapter. It is refering to any kind of a data move.

Alphanumeric, alphanumeric-edited, alphabetic, DBCS
For these receiving items, the following rules apply:
1. The data is aligned at the leftmost character position, and (if necessary) truncated or padded with spaces at the right.
2. If the JUSTIFIED clause is specified for this receiving item, the above rule is modified as described in “JUSTIFIED clause”

COBOL will truncate or pad a field as needed.

Bill O'Boyle · Posted: Tue Dec 07, 2010 2:11 am

In your example, because of the data-lengths, COBOL probably generates an Assembler MVCL or (worst case), calls a COBOL run-time routine.

Bill