Variables

  Variables with names beginning with the string "DTM$UF_" are used to
  control user filters. These variables must be logical variables but
  can be global or local. 

  When tests are run that have associated variables whose names begin
  with the string "DTM$UF_", Digital Test Manager will apply the user
  filters contained in the files referenced by the value of those
  variables. Only a single file may be referenced by each variable. 

  The specified files are executed by DEC Text Processing Utility
  (DECTPU). If more than one user filter variable is associated with a
  test, the files are executed in the lexicographic order of the
  variable names. The user filters are applied before any built-in
  filters that are also specified for the test. 

  User filter files can be located either in OpenVMS directories or in
  Code Management System (CMS) libraries. Files may be
  specified using logical names including logical names that specify
  search lists. Wildcards cannot be used. For files in CMS libraries, 
  the most recent generation on the main line of descent is used.

  Before the first file is executed the file to be filtered is read
  into the DECTPU buffer "filter_buffer". Next, the file specified by
  the logical name DTM$UFDEFINES is executed. The system logical name
  DTM$UFDEFINES references the file SYS$LIBRARY:DTM$UFDEFINES.TPU,
  which contains definitions of a global replace procedure and
  patterns which can be used in building filters. This logical can be
  redefined to point to a custom file. 

  Any errors in accessing the user filter files or in executing the
  DECTPU commands will be reported. However, they will not cause the
  filter operation to fail, and any remaining user and built-in
  filters will be applied. 

  After all the user filters have been applied, the file being
  filtered will be written out. If any built-in filters are also
  specified, they are applied to the newly created file, resulting in
  a second new version. 

  In order to disable a user filter that is defined with a global 
  variable for a particular test, define the value of the variable 
  for the test as a string containing only spaces. For example: 

    MODIFY TEST CHECK_DEVICES /VARIABLE=DTM$UF_DEVICE=" "