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How to put exclusive lock on a file in Cobol


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sudarshan.srivathsav

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Joined: 10 Jul 2012
Posts: 24
Location: USA

PostPosted: Fri Jun 05, 2015 10:36 pm
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I see there is something called "LOCK MODE IS EXCLUSIVE", but it gives me a INVALID keyword error on compiling . It would be of great help if someone could give a FILE-CONTROL section example of how to specify LOCK.

Code:

FILE-CONTROL.                                             
    SELECT IN-FILE  ASSIGN INPUTI FILE STATUS INP-STATUS. 
    SELECT PIPE ASSIGN PIPE                               
    ORGANIZATION IS LINE SEQUENTIAL                       
    ACCESS MODE IS SEQUENTIAL                             
    FILE STATUS PIPE-STATUS.                   


I want to keep a exclusive lock on the file PIPE until I close the same. [/code]
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enrico-sorichetti

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PostPosted: Fri Jun 05, 2015 10:38 pm
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just use DISP=OLD in the jcl.
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sudarshan.srivathsav

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PostPosted: Fri Jun 05, 2015 10:47 pm
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Enrico,

I cannot do that , my output is a unix file as below, the DISP parameter cannot go with PATH, PATHDISP cannot understand OLD. Any other way in program to put exclusive lock on the UNIX file. Basically I am trying to avoid data comingle since another process is also writing data to this pipe, and sometime the data in the pipe gets corrupted.

Code:


//WWCSRSA  JOB CLASS=A,NOTIFY=&SYSUID,MSGCLASS=H,REGION=0M           
//         JCLLIB ORDER=WWCSRS.PROCLIB                               
//STEP1    EXEC PGM=WRITEPIP                                         
//STEPLIB  DD DSN=WWCSRS.PGMLIB,DISP=SHR                             
//PIPE     DD  PATH='/u/wwcsrs/.mfxsplunk',                         
//             PATHDISP=(KEEP,KEEP),                                 
//             FILEDATA=TEXT,DSNTYPE=PIPE,                           
//             PATHOPTS=(ORDWR,OCREAT)                               
//*INPUTI   DD  DSN=WWCSRS.SAMPLE.INPUT.FILE,DISP=SHR               
//INPUTI  DD *                                                       
JOSEPH SMITH        02506240                                         
JAMES JONES         12345678                                         
JOHN JACKSON        00987654                                         

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Bill Woodger

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Joined: 09 Mar 2011
Posts: 7310
Location: Inside the Matrix

PostPosted: Sat Jun 06, 2015 12:15 am
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Can different JOBs not have different (hfs) names for the pipe?

One way, assuming that it is z/OS JOBs only causing this issue, is to make a // INCLUDE for your pipe definition, which also contains a z/OS dataset with DISP=OLD. The additional dataset will provide the "locking" by not allowing another JOB to be selected whilst another JOB is already running.
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Robert Sample

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Joined: 06 Jun 2008
Posts: 8574
Location: Dubuque, Iowa, USA

PostPosted: Sat Jun 06, 2015 3:52 am
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Quote:
I see there is something called "LOCK MODE IS EXCLUSIVE", but it gives me a INVALID keyword error on compiling
Which Enterprise COBOL manual did you find this in? LOCK MODE is used in a number of COBOL versions, but as far as I am aware it is not available for z/OS Enterprise COBOL.
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