For information on specifying collection with user routines enter
    the following commands:

  $ PCA
  PCAA> HELP SET SERVICES /NOUSER_ROUTINE
  PCAA> HELP SET SERVICES /USER_ROUTINE
  PCAA> HELP SET IO_SERVICES /NOUSER_ROUTINE
  PCAA> HELP SET IO_SERVICES /USER_ROUTINE

1  –  Restrictions

    -  PCA will not call, or invoke, your user routine image if it is
       linked with warnings or errors.

    -  You must define a logical name to access the user routine
       image if it is not found in SYS$SHARE.

    -  A system service routine which is invoked from a user-
       supplied routine should be written in the C language (as
       referenced by the /USER_ROUTINE qualifier in the glossary
       of the DIGITAL Performance and Coverage Analyzer for OpenVMS
       Reference Manual). If written in some other languages, it may
       have the effect of locking up PCA. Examples are provided in
       PCA$EXAMPLES.

2  –  Side Effects

    Lost Data Indications will occur in the PCA Analyzer if the user
    supplied routines instructs PCA not to write some data records;