sccsfile(4) FILE FORMATS sccsfile(4)
NAME
sccsfile - format of SCCS file
DESCRIPTION
An SCCS (Source Code Control System) file is an ASCII file.
It consists of six logical parts: the checksum, the delta
table (contains information about each delta), user names
(contains login names and/or numerical group IDs of users
who may add deltas), flags (contains definitions of internal
keywords), comments (contains arbitrary descriptive informa-
tion about the file), and the body (contains the actual text
lines intermixed with control lines).
Throughout an SCCS file there are lines which begin with the
ASCII SOH (start of heading) character (octal 001). This
character is hereafter referred to as the control character
and will be represented graphically as @. Any line
described below that is not depicted as beginning with the
control character is prevented from beginning with the con-
trol character.
Entries of the form DDDDD represent a five-digit string (a
number between 00000 and 99999).
Each logical part of an SCCS file is described in detail
below.
Checksum
The checksum is the first line of an SCCS file. The form of
the line is:
@hDDDDD
The value of the checksum is the sum of all characters,
except those of the first line. The @h provides a magic
number of (octal) 064001, depending on byte order.
Delta table
The delta table consists of a variable number of entries of
one of the following forms:
@s DDDDD/DDDDD/DDDDD
@d <type> <SCCS ID> yr/mo/da hr:mi:se <pgmr> DDDDD DDDDD
@i DDDDD ...
@x DDDDD ...
@g DDDDD ...
@m <MR number>
. . .
@c <comments> . . .
. . .
@e
The first line (@s) contains the number of lines
inserted/deleted/unchanged, respectively. The second line
(@d) contains the type of the delta (normal: D or removed:
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sccsfile(4) FILE FORMATS sccsfile(4)
R), the SCCS ID of the delta, the date and time of creation
of the delta, the login name corresponding to the real user
ID at the time the delta was created, and the serial numbers
of the delta and its predecessor, respectively. The @i, @x,
and @g lines contain the serial numbers of deltas included,
excluded, and ignored, respectively. These lines are
optional. The @m lines (optional) each contain one MR
number associated with the delta; the @c lines contain com-
ments associated with the delta. The @e line ends the delta
table entry.
User names
The list of login names and/or numerical group IDs of users
who may add deltas to the file, separated by new-lines. The
lines containing these login names and/or numerical group
IDs are surrounded by the bracketing lines @u and @U. An
empty list allows anyone to make a delta. Any line starting
with a ! prohibits the succeeding group or user from making
deltas.
Flags
Keywords used internally. See admin(1) for more information
on their use. Each flag line takes the form:
@f <flag> <optional text>
The following flags are defined:
l1 l2f2 l2 . @f t <type of program> @f v <program
name> @f i <keyword string> @f b @f m <module name> @f
f <floor> @f c <ceiling> @f d <default-sid> @f n @f j
@f l <lock-releases> @f q <user defined> @f z <reserved
for use in interfaces>
The t flag defines the replacement for the %Y% identifica-
tion keyword. The v flag controls prompting for MR numbers
in addition to comments; if the optional text is present it
defines an MR number validity checking program. The i flag
controls the warning/error aspect of the ``No id keywords''
message. When the i flag is not present, this message is
only a warning; when the i flag is present, this message
causes a fatal error (the file will not be ``gotten'', or
the delta will not be made). When the b flag is present the
-b keyletter may be used on the get command to cause a
branch in the delta tree. The m flag defines the first
choice for the replacement text of the %M% identification
keyword. The f flag defines the floor release; the release
below which no deltas may be added. The c flag defines the
ceiling release; the release above which no deltas may be
added. The d flag defines the default SID to be used when
none is specified on a get command. The n flag causes delta
to insert a null delta (a delta that applies no changes) in
those releases that are skipped when a delta is made in a
new release (e.g., when delta 5.1 is made after delta 2.7,
releases 3 and 4 are skipped). The absence of the n flag
causes skipped releases to be completely empty. The j flag
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sccsfile(4) FILE FORMATS sccsfile(4)
causes get to allow concurrent edits of the same base SID.
The l flag defines a list of releases that are locked
against editing. The q flag defines the replacement for the
%Q% identification keyword. The z flag is used in certain
specialized interface programs.
Comments
Arbitrary text is surrounded by the bracketing lines @t and
@T. The comments section typically will contain a descrip-
tion of the file's purpose.
Body
The body consists of text lines and control lines. Text
lines do not begin with the control character, control lines
do. There are three kinds of control lines: insert,
delete, and end, represented by:
@I DDDDD
@D DDDDD
@E DDDDD
respectively. The digit string is the serial number
corresponding to the delta for the control line.
SEE ALSO
admin(1), delta(1), get(1), prs(1).
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