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.
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.
@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.
@f <flag> <optional text>
The following flags are defined:
flag defines the replacement for
the %Y% identification keyword.
flag controls prompting for MR numbers
in addition to comments;
if the optional text is present it defines
an MR number validity
flag controls the warning/error
aspect of the ``
No id keywords'' message.
flag is not present,
this message is only a warning;
flag is present,
this message causes a fatal error
(the file will not be ``gotten'', or the delta will not be made).
flag is present
keyletter may be used on the
command to cause a branch in the delta tree.
flag defines the first choice
for the replacement text of the %M% identification keyword.
flag defines the floor release;
the release below which no deltas may be added.
flag defines the ceiling release;
the release above which no deltas may be added.
flag defines the default SID to be used
when none is specified on a
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.
concurrent edits of the same base SID.
flag defines a
of releases that are locked against editing.
flag defines the replacement
for the %n% identification keyword.
flag is used in specialized interface programs.
@I DDDDD @D DDDDD @E DDDDD
respectively. The digit string is the serial number corresponding to the delta for the control line.