logger_init Subroutine

  subroutine logger_init(logfile, stderr_threshold, stdout_threshold, &
                         logfile_threshold)
    !* Author: Chris MacMackin
    !  Date: December 2016
    !
    ! Initalises the master logging object. This subroutine must be
    ! called before the master logger is used. It should only be
    ! called once.
    !
    character(len=*), intent(in)  :: logfile
      !! Name of the log-file to which output will be written
    integer, intent(in), optional :: stderr_threshold
      !! Threshold priority, at and above which messages will be
      !! written to standard error. Defaults to `error`.
    integer, intent(in), optional :: stdout_threshold
      !! Threshold priority, at and above which messages will be
      !! written to standard out. Defaults to `info`.
    integer, intent(in), optional :: logfile_threshold
      !! Threshold priority, at and above which messages will be
      !! written to the log file. Defaults to `trivia`.
    master_logger = logger(logfile, stderr_threshold, stdout_threshold, &
                           logfile_threshold)
  end subroutine logger_init