SCCSFILE(F) UNIX System V
Name
sccsfile - format of an SCCS file
Description
An SCCS 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 information about the file),
and the body (contains the actual text lines intermixed with
control lines). Each logical part of an SCCS file is
described in detail below.
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 which is not depicted as beginning with the
control character is prevented from beginning with the
control character. Entries of the form DDDDD represent a
five digit string (a number between 00000 and 99999).
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 @hR 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 <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 (currently, normal: D,
and 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.
Flags
Keywords used internally (see admin(CP) 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>
The t flag defines the replacement for the identification
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
will cause a ``fatal'' error (the file will not be gotten,
or the delta will not be made). When the b flag is present
the -b option may be used with the get command to cause a
branch in the delta tree. The m flag defines the first
choice for the replacement text of the sccsfile.F
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 causes get to allow
concurrent edits of the same base SID. The l flag defines a
list of releases that are locked against editing (get(CP)
with the -e option). The q flag defines the replacement for
the identification keyword.
Comments
Arbitrary text surrounded by the bracketing lines @t and @T.
The comments section typically contains a description of the
file's purpose.
Body
The body consists of text lines and control lines. Text
lines don't begin with the control character, control lines
do. There are three kinds of control lines:
insert, delete, and end, as follows:
@I DDDDD
@D DDDDD
@E DDDDD
The digit string (DDDDD) is the serial number corresponding
to the delta for the control line.
See Also
admin(CP), delta(CP), get(CP), prs(CP)
Standards Conformance
sccsfile is conformant with:
AT&T SVID Issue 2, Select Code 307-127.
(printed 2/15/90) SCCSFILE(F)