VMS Help CMS, DIFFERENCES, /CLASS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Compares the contents of two classes. If the particular generation
    of any element, that is a member of the class, differs between the
    classes, CMS creates a file that contains a listing of the class
    members that differ between them. If the contents of the classes
    are the same, CMS issues a message to that effect and does not create
    a differences file (unless the /FULL qualifier is in effect). The
    /CLASS qualifier must be specified prior to any other qualifiers.

       Format:

          DIFFERENCES/CLASS  class1 class2

1 - Command Parameters

 class1

    Specifies the first class that is to be compared.

 class2

    Specifies the second class that is to be compared.

2 - Description

    The DIFFERENCES/CLASS command compares the contents of two
    classes. If CMS finds differences, it creates a file named
    first-class-name.DIF in your current default directory (unless
    /OUTPUT is in effect.) If the contents of the classes are the
    same, it issues a message to that effect and does not create a
    differences file.

    Note: Both classes must reside in the same library of the search
    list or an error will occur.

    A difference is defined as one of the following:

    o  A particular generation of an element is a member of one
       class but no generation of the element is a member of the
       other class.

    o  One particular generation of an element is a member of one
       class and a different generation of the same element is a
       member of the other class.

    Only the generations that differ are displayed in the differences
    file (unless you specify /FULL).

    A heading at the beginning of the differences file includes the
    name of the user that issued the command, the date and time the
    command was issued, and the class names of the two classes being
    compared.

3 - Qualifiers

 3.1 - /APPEND

    Controls whether CMS appends the command output to an existing
    file, or creates a new file. If you specify /APPEND and the output
    file does not exist, CMS creates a new file. If you do not provide
    an output file specification (see the description for /OUTPUT),
    CMS searches your current default directory for a file with the
    file name specified in the file1 parameter and the file type .DIF.

 3.2 - /FULL

    Directs CMS to include a complete listing in the output file,
    including both identical and different generations between
    class1 and class2.

 3.3 - /IGNORE=(keyword[,...])

    Specifies one or more of the following keywords. Each keyword
    indicates a type of difference to be ignored during the
    comparison.

    Keyword          Ignored Difference

    FIRST_VARIANT    Directs CMS to ignore any differences where the
                     generation in one class is the first variant of
                     the generation in the other class. For example
                     generation 2C1 is a first variant of generation
                     2 and generation 4B6D1 is a first variant of
                     generation 4B6.

 3.4 - /LOG (D)

    Controls whether CMS displays success and informational messages
    on the default output device. By default, if the command executes
    successfully, CMS displays a success message. If you specify
    /NOLOG, success and informational messages are suppressed. Any
    warning, error, or fatal error messages are displayed regardless
    of whether /LOG or /NOLOG is specified.

 3.5 - /OCCLUDE[=option,...]

    Controls whether CMS selects the first instance of the specified
    object, or all instances of the specified object in the library
    search list. The options field contains one or more keywords
    associated with the name of the object. The options field can
    contain the following keywords:

       ALL--equivalent to (ELEMENT, CLASS)
       ELEMENT (D)
       NOELEMENT
       CLASS (D)
       NOCLASS
       NONE--equivalent to (NOELEMENT, NOCLASS)

    You can specify either ALL or NONE, or any combination of the
    [NO]ELEMENT and [NO]CLASS keywords.

    By default, CMS performs occlusion for all objects; that is, CMS
    selects only the first occurrence of a specified object.

 3.6 - /OUTPUT[=file-specification]

    Directs CMS to write output to the specified file. CMS creates a
    new file if you do not specify /APPEND. If you omit the /OUTPUT
    qualifier (or if you specify /OUTPUT but do not provide a file
    specification), CMS creates a file with the file name specified in
    the class1 parameter and the file type .DIF. If you specify a file
    name but omit the file type component, CMS writes the output to a
    file with the specified file name and a file type of .DIF.

 3.7 - /NOOUTPUT

    Directs CMS to execute a comparison without creating an output
    file. This form of the comparison may be significantly faster
    because CMS stops the transaction when it encounters the first
    difference.

 3.8 - /PARALLEL

    Controls whether the differing member generations from the two
    classes are formatted side by side. If you specify /PARALLEL,
    the differences from the first class are displayed on the left
    and the differences from the second class are displayed on the
    right. The heading of the differences report displays the class
    name of the first class on the left and the class name of the
    second class on the right.

    By default, the width of the listing is 132. Use the /WIDTH
    qualifier to control the width. Vertical lines separate the text
    on the left side of the report from the text on the right side.
    The text from each of the classes is allotted equal space (half
    the width of the full report).

    If a line from one of the classes being compared is longer than
    half the width of the full report, the line is truncated on the
    right. A plus sign (+) is printed at the end of the line to
    indicate that the line has been truncated.

 3.9 - /SHOW=(keyword[,...])

    Specifies one or more of the following keywords. Each keyword
    indicates a type of class difference to show.

    Keyword                   Difference Type

    GENERATION_DIFFERENCES    Directs CMS to show the difference if the
                              generation in one class differs from the
                              generation in the other class but one
                              generation isn't a variant of the other
                              generation.

    VARIANT_DIFFERENCES       Directs CMS to show the difference if the
                              generation in one class differs from the
                              generation in the other class and one
                              generation is a variant of the other. One
                              generation will be a variant of the other
                              if at some point in the path between one
                              generation and the other a generation is
                              reserved and replaced /VARIANT.

    If the /SHOW qualifier is not specified, both generation differences
    and variant differences are shown. If a generation of an element is
    in one class but no generation of the element is in the other class
    then the difference is always shown regardless of whether the /SHOW
    qualifier is specified or not.

 3.10 - /WIDTH=n

    Specifies the limit for the width of the differences report. The
    value n is required and must be an integer in the range 48 to 511.
    If n is less than 48, 48 is used. If n is more than 511, 511 is
    used. The default width is the same as the width of the output
    device.

    The width of the report is rounded down to the nearest multiple
    of 8 minus 1. CMS rounds down so that if you have specified the
    /PARALLEL qualifier, CMS correctly interprets the horizontal tabs
    in the generation comment on the right. Thus, for example, if you
    specify a value of 100 on the /WIDTH qualifier, the actual width
    is 95.