/sys$common/syshlp/helplib.hlb Lexicals, F$PRIVILEGE, Example  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  $ PROCPRIV = F$PRIVILEGE("OPER,GROUP,TMPMBX,NONETMBX")
  $ SHOW SYMBOL PROCPRIV
    PROCPRIV = "FALSE"

      The F$PRIVILEGE function is used to test whether the process
      has OPER, GROUP, and TMPMBX privileges and if you do not have
      NETMBX privileges.

      The process in this example has OPER (operator), GROUP, TMPMBX
      (temporary mailbox), and NETMBX (network mailbox) privileges.
      Therefore, a value of FALSE is returned because the process has
      NETMBX privilege, but NONETMBX was specified in the priv-states
      list. Although the Boolean result for the other three keywords
      is true, the entire expression is declared false because the
      result for NONETMBX was false.