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finding whether the file is empty or not

 
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Beswar
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Joined: 04 Feb 2003
Posts: 33
Topics: 15

PostPosted: Tue May 11, 2004 10:00 am    Post subject: finding whether the file is empty or not Reply with quote

Hi All,

Is there any way to find whether file empty or not in the COBOL program. I mean without opening the file and read. Is there any utility like IDCAMS any other utlities that will find whehter the file is empty or not. If any thing is there can I call the utility in the program to find status of the file.

Thanks
Eswar
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kolusu
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PostPosted: Tue May 11, 2004 10:05 am    Post subject: Reply with quote

Beswar,
Yes it is possible to call IDCAMS from cobol but that would involve a lot of overhead. It would be simple to open and read the file and check if it is empty. All this takes is just 2 statements.

Another alternative is to check the file if it empty upfront , before you execuete your cobol program. Take a look at my post in this topic for various examples of checking an empty file.

http://www.mvsforums.com/helpboards/viewtopic.php?t=1285&highlight=empty

Hope this helps...

Cheers

Kolusu
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Beswar
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Joined: 04 Feb 2003
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PostPosted: Tue May 11, 2004 10:19 am    Post subject: Reply with quote

Kolusu,

Thanks for your the reply. But currently we already calling the IDCAMS through our program and this is usefull to copy all the files into one file. But when we call the IDCAMS I really don't know how to get the return code to find whether the file is empty. Do you know what is the layout of the i need to create to get the return code into the COBOL program.

Thanks
Eswar
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kolusu
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PostPosted: Tue May 11, 2004 3:16 pm    Post subject: Reply with quote

Beswar,

There is no special layout to get the return-code from IDCAMS. Here is a sample of program which will check if the file is empty by invoking IDCAMS. Even though I am providing the solution, this approach seriously needs a re-design. I am confused as to why you want to take long route instead of 3 statements(open read & close) which is fairly simple. I would like to know your justification of using this approach.

Code:

CBL DATA(24)                                             
IDENTIFICATION DIVISION.                                 
PROGRAM-ID.    CALLDCAM                                 
DATE-COMPILED.                                           
ENVIRONMENT DIVISION.                                   
CONFIGURATION SECTION.                                   
INPUT-OUTPUT SECTION.                                   
FILE-CONTROL.                                           
                                                         
      SELECT IDCAMS-FILE                                 
      ASSIGN TO IDCOMND                                 
      ORGANIZATION IS SEQUENTIAL.                       
                                                         
DATA DIVISION.                                           
FILE SECTION.                                           
                                                         
FD IDCAMS-FILE                                           
    RECORDING MODE IS F                                 
    LABEL RECORDS ARE STANDARD                           
    BLOCK CONTAINS 0 RECORDS                             
    DATA RECORD IS IDCAMS-REC.                           
                                                         
01 IDCAMS-REC                  PIC X(80).               

WORKING-STORAGE SECTION.                                     
01 WS-FILE-NAME                PIC X(44) VALUE SPACES.                   
01 WS-DYN-MODULE               PIC X(08) VALUE 'IDCAMS'.   
01 WS-COMMAND-REC              PIC X(80) VALUE SPACES.       
                                                             
01 PARM-OPTIONS.                                             
   05 PARM-LENGTH              PIC S9(04) COMP VALUE 0.     
                                                             
01 DD-OPTIONS.                                               
   05 DD-LENGTH                PIC S9(04) COMP VALUE +48.   
   05 FILLER                   PIC X(32) VALUE LOW-VALUES.   
   05 SYSIN-DD                 PIC X(08) VALUE 'IDCOMND'.   
   05 SYSPRINT-DD              PIC X(08) VALUE 'SYSOUT'.     

PROCEDURE DIVISION.                                             
                                                                 
      OPEN OUTPUT  IDCAMS-FILE                                   
                                                                 
      MOVE 'YOUR EMPTY FILE TO CHECK' TO WS-FILE-NAME                 
                                                                 
      STRING                                                     
           ' PRINT IDS('          DELIMITED BY SIZE             
           QUOTE                  DELIMITED BY SIZE             
           WS-FILE-NAME           DELIMITED BY SPACE             
           QUOTE                  DELIMITED BY SIZE             
           ') CHARACTER COUNT(1)' DELIMITED BY SIZE             
           INTO WS-COMMAND-REC                                   
      END-STRING.                                               
                                                               
      WRITE IDCAMS-REC FROM WS-COMMAND-REC
      CLOSE IDCAMS-FILE                                         
       CALL WS-DYN-MODULE USING PARM-OPTIONS, DD-OPTIONS         
                                                                 
      EVALUATE RETURN-CODE                                       
          WHEN 0                                                 
               DISPLAY ' THE FILE HAS ATLEAST 1 RECORD'         
          WHEN 4                                                 
               DISPLAY ' THE FILE IS EMPTY'                     
          WHEN 12                                               
               DISPLAY ' THE FILE IS NOT IN CATALOG'             
               DISPLAY ' CHECK THE FILE NAME'                   
          WHEN OTHER                                             
               DISPLAY ' CATASTROPHIC ERROR'                     
      END-EVALUATE 
                                             
      GOBACK                                                     
      .                                                         


The JCL to run this program is below. pay attention to the IDCOMND ddname in the program

Code:

//STEP0100 EXEC PGM=CALLDCAM                                 
//STEPLIB  DD DSN=YOUR PGM LOADLIB,                     
//            DISP=SHR                                       
//         DD DSN=SYS1.LINKLIB,                               
//            DISP=SHR                                       
//IDCOMND  DD DSN=USERID.COMMAND.FILE,
//            DISP=(NEW,CATLG,DELETE),
//            UNIT=SYSDA,
//            SPACE=(TRK,(1,1),RLSE)
//SYSPRINT DD SYSOUT=*                                       
//SYSOUT   DD SYSOUT=*                                       
/*


Hope this helps...

Cheers

Kolusu
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mf_user
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PostPosted: Tue Feb 21, 2006 9:15 am    Post subject: Reply with quote

Hi,

This is simply superb. Would you please let me know why do we use
PARM-LENGTH though there is no linkage section in the program.
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kolusu
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PostPosted: Tue Feb 21, 2006 9:41 am    Post subject: Reply with quote

mf_user,

Check this link which will answer your query.

http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DGT2I230/D.2.3?DT=20040628101835

Kolusu
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mf_user
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PostPosted: Tue Feb 21, 2006 9:58 am    Post subject: Reply with quote

Thanks for the link Kolusu. I think it is bit advance for the beginner like me... Smile
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