PUTENV UTILITY How to reopen previously allocated files

SVazifdar · New User Joined: 21 Apr 2006 Posts: 14

I used the PUTENV example to dynamically allocate files and it works fine. However I would like to enhance the program to do the following and would like know if it is possible.

I have a file that has header records for several customers and detail records. However the header and details for the same customer appear at different places in the file. At the present time I do not want to sort the file.

Customer1
Details
Customer2
Details
Customer1
Details
Customer3
Details
Customer1
Details
Customer4
Details

I have a program that dynamically allocates files and writes records to the files.

I allocate the file for customer1, write records, and close the file for customer1. That works fine. Next I allocate file for customer2, write records, and close the file. That works fine.

Now I would to process customer1 again so I want reopen the previously allocate file for customer1 and append records to it. Is that possible and how could it be done. Please help.

Thanks

S. Vazifdar

dick scherrer · Posted: Sat Mar 07, 2009 3:23 am

Hello,

mmwife · Super Moderator Joined: 30 May 2003 Posts: 1592

Hi,

You might try to use a MOD disposition. If that doesn't work, a FREE=CLOSE along with the MOD might do the trick.

Douglas Wilder · Posted: Mon Mar 09, 2009 9:15 pm

If you do not close nor free the file for customer1 and use a different ddname for customer2, you could just write to the customer1 and customer2 files as needed. Otherwise you would need to free the ddname and re-allocate customer1 with disp=mod. This will add a lot of overhead to the process, and I believe that it would save resources to sort the file so that this is not needed.