Read all members of a PDS with COBOL

Searchman · New User Joined: 28 Dec 2006 Posts: 80 Location: France

My previous post is lost (yesterday), so I write it again.

Is there a way to read a PDS file with a COBOL program ?

William Thompson · Posted: Thu Jul 26, 2007 12:50 pm

Sure, point an FD to a DD that is a PDS member and read it....

balakrishna reddy · Posted: Thu Jul 26, 2007 3:03 pm

Hi William,

Can you explain this a bit more elaborately

William Thompson · Posted: Thu Jul 26, 2007 3:09 pm

kgumraj · Posted: Thu Jul 26, 2007 3:15 pm

Hi,

You can read a PDS in cobol program, as you do to PS file.
As PDS and PS are one and the same internally, while externally (We) see that differently, When you create a PDS some space is allocated for storing the member information.

EX:
you have 3 members
and you access 2nd member, when accessing it will open the records of 2nd member. But internally all the members come in order they are created.

dick scherrer · Posted: Thu Jul 26, 2007 6:14 pm

Hello,

I believe this is mis-leading

kgumraj · Posted: Thu Jul 26, 2007 6:21 pm

Hi Dick,

I was not Misleading, but little explanatory.
My first line told the answer and the other lines was explanation what was the reason behind that.

If that causes confusion do excuse.

Searchman · New User Joined: 28 Dec 2006 Posts: 80 Location: France

Sorry, but I don't understand very well

William wrote :

dick scherrer · Posted: Fri Jul 27, 2007 2:12 am

Hello,

No, you cannot name only the dataset and not the member in your jcl and read all of the members. The access method does not support that.

If you run a multi-step process, you could list all of the member names, from the list generate concatenated dd statements for each member, then use the generated dd statements in your process.

Depending on how many members are in the pds, you may need to create multiple sets.

superk · Posted: Fri Jul 27, 2007 2:15 am

You'd want to use the ISPF LMMLIST Service, among possible others (LMINIT, LMOPEN, LMGET, LMPUT, LMCLOSE) to access the PDS directory structure programatically.

Douglas Wilder · Posted: Fri Jul 27, 2007 2:25 am

I believe that what you are asking for could be done by dynamically allocating one member of the PDS, opening, reading, and closing that member, and freeing and dynamically allocating the next member, etc.

There are other postings on this forum on how to do the dynamic allocation. One way is for the COBOL program to call a REXX to do the free and allocate.