SIC MODIFIED

        [SIC\]SIC MODIFIED FileName StrName

    Check  if a "file" was modified since last call, and fill the Sic struc-
    ture named "StrName" accordingly. The file can be a regular  file  or  a
    directory. If file is a symbolic link, evaluation is made on its target.
    On first call, the structure is set up and the file is assumed modified.
    On  subsequent  calls, file and calling dates are compared and modifica-
    tion status is evaluated. In case of doubt (e.g. modification  time  un-
    changed at the file system precision), a modification is assumed.

    The output structure has the following (scalar) components:
      - StrName%FILE: the file name (character string),
      - StrName%MTIME: the file modification time (long integer, in
        nanoseconds since 01-jan-1970),
      - StrName%PTIME: last time a modification was proved (long integer, in
        nanoseconds),
      - StrName%MODIF: file was (or may have been) modified or not since
        last call (logical)
    The structure must be a user-defined, global, variable. If the structure
    or its elements are missing, they will be created at first call.