HP-UX Reference (11i v2 04/09) - 4 File Formats (vol 8)

r
rcsfile(4) rcsfile(4)
NAME
rcsfile - format of RCS files
DESCRIPTION
An RCS file is an ASCII file. Its contents are described by the grammar below. The text is free format,
i.e., spaces, tabs and newline characters have no significance except in strings. Strings are enclosed by
@
symbols. If a string contains the @
symbol, the symbol must be doubled.
The meta syntax uses the following conventions:
| (bar) Separates alternatives.
{...} (braces) Encloses optional phrases.
{...}* Encloses phrases that may be repeated zero or more times.
{...}+ Encloses phrases that must appear at least once and may be repeated.
<...> Encloses nonterminals.
RCS File Grammar
Identifiers are case sensitive. Keywords are in lowercase only. The sets of keywords and identifiers may
overlap.
<rcstext> ::= <admin> {<delta>}* <desc> {<deltatext>}*
<admin> ::= head {<num>};
access {<id>}*;
symbols {<id> : <num>}*;
locks {<id> : <num>}*; {strict ;}
comment {<string>};
<delta> ::= <num>
date <num>;
author <id>;
state {<id>};
branches {<num>}*;
next {<num>};
<desc> ::= desc <string>
<deltatext> ::= <num>
log <string>
text <string>
<num> ::= {<digit>{.}}+
<digit> ::= 0|1|...|9
<id> ::= <letter>{<idchar>}*
<letter> ::= A|B|...|Z|a|b|...|z
<idchar> ::= Any printing ASCII character except space,
tab, carriage return, newline, and <special>.
<special> ::= ;|:|,|@
<string> ::= @{any ASCII character, with "@" doubled}*@
RCS File Structure
The
<delta> nodes form a tree. All nodes whose numbers consist of a single pair (e.g., 2.3, 2.1, 1.3, etc.)
are on the trunk, and are linked through the next field in order of decreasing numbers. The head field
in the <admin> node points to the head of that sequence (i.e., contains the highest pair).
All
<delta> nodes whose numbers consist of 2n fields (n>=2) (e.g., 3.1.1.1, 2.1.2.2, etc.) are linked as
follows. All nodes whose first (2n)-1 number fields are identical are linked through the next field in
order of increasing numbers. For each such sequence, the <delta> node whose number is identical to
HP-UX 11i Version 2: September 2004 − 1 − Hewlett-Packard Company Section 4−−273