sccsfile(4) sccsfile(4)
NAME
sccsfile - format of SCCS file
DESCRIPTION
An SCCS (Source Code Control System) file is an ASCII file. It con-
sists of six logical parts: the checksum, the delta table (information
about each delta), user names (login names and/or numerical group IDs
of users who may add deltas), flags (definitions of internal key-
words), comments (arbitrary descriptive information about the file),
and the body (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 graphi-
cally 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
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sccsfile(4) sccsfile(4)
The first line (@s) contains the number of lines
inserted/deleted/unchanged, respectively. The second line (@d) con-
tains the type of the delta (normal: D or removed: 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 comments 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:
@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 text for the %Y% keyword. The v
flag controls prompting for MR numbers in addition to comments; if the
optional argument 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
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only a warning; when the i flag is present, this message causes a
fatal error (the file will cannot be retrieved with "get", 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% 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 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 specialized inter-
face programs.
Comments
Arbitrary text is surrounded by the bracketing lines @t and @T. The
comments section typically will contain a description 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 respec-
tively by:
@I DDDDD
@D DDDDD
@E DDDDD
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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