sccsfile(FP)                   6 January 1993                   sccsfile(FP)


 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).

    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 in this description 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.

    Each @m line (optional) contains 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

    This list of login names and/or numerical group IDs includes 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 brack-
    eting lines @u and @U.  An empty list allows anyone to make a delta.

    Flags

    Flags are 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 pro-
    gram.  The i flag controls the warning/error aspect of the ``No id key-
    words'' 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 received, 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 (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 com-
    pletely 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

    Comments are arbitrary text surrounded by the bracketing lines @t and @T.
    The comments section typically contains a description of the file's pur-
    pose.

    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, 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.