filespec

    Specifies a character string containing the file specification
    to be searched for. If the device or directory names are omitted,
    the defaults from your current default disk and directory are
    used. The F$SEARCH function does not supply defaults for a file
    name or type. If the version is omitted, the specification for
    the file with the highest version number is returned. If the
    filespec argument contains the asterisk (*)  or the percent
    sign (%)  wildcard characters, each time F$SEARCH is called, the
    next file specification that agrees with the filespec argument
    is returned. A null string is returned after the last file
    specification that agrees with the filespec argument.

 stream-id

    Specifies a positive integer representing the search stream
    identification number.

    The search stream identification number is used to maintain
    separate search contexts when you use the F$SEARCH function
    more than once and when you supply different filespec arguments.
    If you use the F$SEARCH function more than once in a command
    procedure and if you also use different filespec arguments,
    specify stream-id arguments to identify each search separately.

    If you omit the stream-id argument, the F$SEARCH function starts
    searching at the beginning of the directory file each time you
    specify a different filespec argument.