HP OpenVMS Systems

RMS File Defered Write (FAB$V_DFW) Status?

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The Question is:

 
I create a file using FDL with the option DEFERRED_WRITE YES
  But when I analyze the file I just created the DEFERRED_WRITE option does not
 show up in the resulting FDL.  Based on program run accounting statistics
 using that file I am not sure if it really is set to DEFERRED WRITE.
  How can I determine if a file is set to 'DEFERRED WRITE' ?
       thanks - tc
 

The Answer is :

 
  Please contact the support center, as details on the file and the
  file organization will be required -- the defered write (FAB$V_DFW)
  option applies only to relative and indexed files, for instance.
 
  Applications can request defered writes, as well.
 
  FDL can be used to create what the OpenVMS Wizard will here refer to
  as the non-volatile file attributes, such as an indexed file key, an
  allocation or extension size, or to specify run-time attributes.
  That said, there is no permanent storage within the file for run-time
  attributes, meaning these must be explicitly (re)set when needed.
 
  In order to access these from FDL, you would have to call FDL$PARSE
  to create and load the FABs and RABs.  For higher level languages,
  this can be tricky (and write access into the FABs and RABs used by
  higher-level languages is often unsupported) and the OpenVMS Wizard
  would recommend use of native language support for access to the FAB
  and RAB structures.
 
  For further details, please also see the RMS Reference Manual section
  on FDL, and please see the OpenVMS File Applications manual for
  details on various FDL run-time routines.
 

  

     

     
answer written or last revised on ( 10-JUL-2002 )
     
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