sccsfile(4)

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 information 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 control 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> <SID>  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: 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 MRnumber 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 for the %Y% 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 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 (for example, 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 %n% identification keyword. The z flag is used in specialized interface 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 by:

   @I DDDDD
   @D DDDDD
   @E DDDDD

respectively. The digit string is the serial number corresponding to the delta for the control line.

References

admin(1), delta(1), get(1), prs(1)