Chapter 19  LINKING
 
If  you wish to link a program so that it may share HBOOK4 histograms with
TOPDRAWER, you need to do the following:

     1.  Insert the following lines of code into your main program.
              INTEGER HCREATEG
              PARAMETER IHSIZE=100000
              COMMON /PAWC/MEMORY(IHSIZE)
                   ......
              ISTAT=HCREATEG('region_name',MEMORY,IHSIZE)
              IF (ISTAT .le.  0) STOP 'Can not create region'
              CALL HLIMIT(IHSIZE)
         You may adjust the IHSIZE to the proper value.

     2.  When you link you must also include:
              TOPDRAWER_DIR:TD_GROUP/OPT
         To give users in your group only read access to your histograms.
              ISTAT=HCREATEG('region_name',MEMORY,-IHSIZE)
                   or link using....
              TOPDRAWER_DIR:TD/OPT
         TD_GROUP  uses  a  modified  version  of HCREATEG rather than the
         standard CERN version.  The modified one in addition  to  setting
         up  group  read/write  protection  on  the  section also prevents
         creation of the same global section by more than  1  person.   It
         creates  a new version instead.  It will type out the name of the
         created global section.  The modified version will create a  read
         only section if -IHSIZE is passed to it.

         To  create  a  global  section HCREATEG must open a scratch file.
         The modified version attempts to do  this  on  SYS$SCRATCH:.   By
         reassigning  the  scratch  device you may put this file on a disk
         with enough quota.
              $ DEFINE SYS$SCRATCH USR$SCRATCH:[name]

For information about using the TD subroutines:
SEE:SUBROUTINES