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.