OPS/REXX Built-in Functions › OPSVALUE Function › Examples: OPSVALUE

Examples: OPSVALUE

Review the following examples for a better understanding of OPSVALUE:

• Example 1: The following example shows how you can use a serialized update of global variables to implement an enqueue/dequeue strategy that is similar to the RDF table editor:

enqsys = OPSINFO('MSFID'); vrc=0       /* Get our sysid           */
enqnew = 'HELD BY' userid 'ON' enqsys  /* New value for enqueue   */
if sysid <> '' then do                 /* Remote resource?        */
  Address 'OPSCTL' "MSF DEFAULT SYSTEM("sysid")"  /* Xsys request*/
  enqsys = sysid                       /* Sysid for variable name */
end                                                                
enqvar = 'GLVTEMP0.ENQ.'enqsys'.'resource  /* ENQ variable name   */
do i=1 to 100 while vrc=0              /* Try 100 times or works  */
  enqold = OPSVALUE(enqvar,'V')        /* Get current ENQ value   */
  if enqold = '' | enqold = enqvar then  /* If ENQ is free        */
    vrc = OPSVALUE(enqvar,'C',enqnew,enqold)  /* Grab ENQ         */
  else                                                             
    rc = OPSWAIT(1)                    /* Wait a little and retry */
end                                                                
if sysid <> '' then                    /* Reset Xsys environment  */
  Address 'OPSCTL' "MSF DEFAULT SYSTEM(*)"                         
if vrc = 0 then                        /* Test ENQ obtained       */
  say 'Enqueue of' enqsys'.'resource 'failed. enqold  /* Failure  */
else                                                               
  deqlist = deqlist enqvar             /* Save var name for DEQ   */

• Example 2: The following example deletes variables that are subnodes of GLOBALA.TEST. if they have not been referenced in one year. The last reference date is word 12 of the variable data record.

xrc = OPSCLEDQ()                       /* Clear EDQ               */
vcnt = OPSVALUE('GLOBALA.TEST.','T')   /* Get data on subnodes    */
do i=1 to vcnt while QUEUED() > 0      /* Loop thru subnode data  */
  pull varname                         /* First record is name    */
  pull vardata                         /* Second is data record   */
  if WORD(vardata,12) = 'NONE' then    /* Real old variable       */
    vardate = 19900101                 /* Set to ancient date     */
  else                                 /* Get data as yyyymmdd    */
    vardate = SPACE(TRANSLATE(WORD(vardata,12),' ','/'),0)         
  if DATE('B') - DATE('B',vardate,'S') > 365 then  /* Not used?   */
    rcnt = OPSVALUE(varname,'R')       /* Delete var + subnodes   */
end

• Example 3: The following example DROPS (deletes) all variables that are subnodes of GLOBALA.TEST. and sets GLOBALA.TEST. to uninitialized:

val = OPSVALUE('GLOBALA.TEST.','D')    /* Delete all subnodes     */

• Example 4: The following example requests high-level security for the highest level of authority that is allowed. High-level security reduces overhead in applications that perform a large number of global variable operations.

sec = OPSVALUE('GLOBAL.READWRITE','H')  /* Request update auth    */
if sec <> 'AUTH' then
  sec = OPSVALUE('GLOBAL.READONLY','H')  /* Try read only auth    */