sccsfile(5)sccsfile(5)Namesccsfile - format of SCCS file
Description
An SCCS file is an ASCII file that consists of six logical parts.
These six parts include checksum, 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 body (contains the actual text lines inter‐
mixed with control lines).
Throughout an SCCS file there are lines that 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 that is not shown beginning with the
control character is prevented from beginning with the control charac‐
ter.
Entries of the form represent a 5-digit string number between 00000 and
99999.
The logical parts of an SCCS file, described in detail, are:
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 provides a magic number of
(octal) 064001.
Delta table
The delta table consists of a variable number of entries of the
form:
@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 <comment> ...
.
.
.
@e
The first line contains the number of lines inserted/deleted/unchanged,
respectively. The second line contains the type of the delta (normal:
and removed: 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 pre‐
decessor, respectively.
The and lines contain the serial numbers of deltas included, excluded,
and ignored, respectively. These lines are optional. The lines
(optional) each contain one number associated with the delta. The
lines contain comments associated with the delta.
The line ends the delta table entry.
User names
The list of login names and numerical group ID of users who may
add deltas to the file, separated by newlines. The lines con‐
taining these login names and numerical group ID are surrounded
by the bracketing lines and An empty list allows anyone to make
a delta.
Flags
Keywords used internally. See 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
@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 flag defines the replacement for the identification keyword.
The flag controls prompting for numbers, in addition to comments. If
the optional text is present, it defines an number-validity checking
program.
The flag controls the warning/error aspect of the ``No id keywords''
message. When the flag is not present, this message is only a warning;
when the flag is present, this message will cause a fatal error (the
file will not be retrieved or the delta will not be made).
When the flag is present, the option can be specified with the command
to cause a branch in the delta tree.
The flag defines the first choice for the replacement text of the iden‐
tification keyword.
The flag defines the ``floor'' release: the release below which no
deltas may be added.
The flag defines the ``ceiling'' release: the release above which no
deltas may be added.
The flag defines the default SID to be used when none is specified on a
command.
The 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. For example, when delta 5.1 is made after delta 2.7,
releases 3 and 4 are skipped. The absence of the flag causes skipped
releases to be completely empty.
The flag causes to allow concurrent edits of the same base I.
The flag defines a list of releases that are locked against editing
with the option.
The flag defines the replacement for the identification keyword.
The flag is used in certain specialized interface programs.
Comments
Arbitrary text surrounded by the bracketing lines and The com‐
ments section typically contains 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 by the following:
@I DDDDD
@D DDDDD
@E DDDDD
The digit string is the serial number corresponding to the delta for
the control line.
See Also
(1), delta(1), get(1), prs(1), sccs(1)
An Introduction to the Source Code Control System,
Eric Allman, Supplementary Documentation, Vol. II.
sccsfile(5)
