Troubleshooting

In this section, I will review the points that seem to be the most frequent causes of trouble when beginning to use DASH.

• If you have an access or segmentation violation associated with calling an entrypoint, this is probably DASH attempting to call an entrypoint that is nonexistant. These problems typically occur when you are adding a new module or adding an entrypoint to an existing module. There are three likely causes:
  • In DASH_DECL, the entrypoint is declared to DASH with DASH_DEC_MOD, but is not declared EXTERNAL.
  • The entrypoint is declared in DASH_DECL but not coded in the module, or coded with a different name.
  • The entrypoint is declared in DASH_DECL and coded in the module, but you have not linked to the module object file. This should cause an unsatisfied external link error. Fix your options file (VMS) or Makefile (Unix).
• You have added a new module, there are no link errors, but it is not present when you look for it with the STATUS command. You have forgotten to add the module in DASH_DECL: you need to add calls to DASH_DEC_MOD for each entrypoint and declare them EXTERNAL.
• Most DASH commands can be given in any order. But watch out for the ``*'' shortcut. For BOOK, FILTER and CALL, the ``*'' represents ``all modules in the analysis path''. Therefore, this shortcut should be used after you set up the analysis path.
• The analysis path should not include the read-module and write-module. The PATH command is used to specify the analysis modules in between. The read-module always comes first for each event, and the write-module always comes last. Usually there is only one read-module and write-module for a given DASH executable and you never have to specify anything; if you have more than one, see SET/READ and SET/WRITE for more information.
• Some problems may be related to the changing state of the CERN packages, KUIP in particular. For example, the way KUIP handles optional arguments in release 93C introduced a bug that means you have to specify all the arguments for RUNLIST/INCLUDE and RUNLIST/EXCLUDE. This is not a problem in earlier versions and will be fixed in release 93D. Another problem that seems to occur after a new CERN release is that the code in DASH_DEF needs to be rebuilt. This is the CLI definition routine and is built from DASH_DEF.CDF using the program KUIPC.