xref: /aosp_15_r20/external/libvpx/keywords.dox (revision fb1b10ab9aebc7c7068eedab379b749d7e3900be)
1*fb1b10abSAndroid Build Coastguard Worker/*!\page rfc2119 RFC2119 Keywords
2*fb1b10abSAndroid Build Coastguard Worker
3*fb1b10abSAndroid Build Coastguard Worker      The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
4*fb1b10abSAndroid Build Coastguard Worker      NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and
5*fb1b10abSAndroid Build Coastguard Worker      "OPTIONAL" in this document are to be interpreted as described in
6*fb1b10abSAndroid Build Coastguard Worker      <a href="http://www.ietf.org/rfc/rfc2119.txt">RFC 2119.</a>
7*fb1b10abSAndroid Build Coastguard Worker
8*fb1b10abSAndroid Build Coastguard WorkerSpecifically, the following definitions are used:
9*fb1b10abSAndroid Build Coastguard Worker
10*fb1b10abSAndroid Build Coastguard Worker\section MUST
11*fb1b10abSAndroid Build Coastguard Worker\anchor REQUIRED
12*fb1b10abSAndroid Build Coastguard Worker\anchor SHALL
13*fb1b10abSAndroid Build Coastguard Worker   This word, or the terms "REQUIRED" or "SHALL", mean that the
14*fb1b10abSAndroid Build Coastguard Worker   definition is an absolute requirement of the specification.
15*fb1b10abSAndroid Build Coastguard Worker
16*fb1b10abSAndroid Build Coastguard Worker\section MUSTNOT MUST NOT
17*fb1b10abSAndroid Build Coastguard Worker\anchor SHALLNOT
18*fb1b10abSAndroid Build Coastguard Worker   This phrase, or the phrase "SHALL NOT", mean that the
19*fb1b10abSAndroid Build Coastguard Worker   definition is an absolute prohibition of the specification.
20*fb1b10abSAndroid Build Coastguard Worker
21*fb1b10abSAndroid Build Coastguard Worker\section SHOULD
22*fb1b10abSAndroid Build Coastguard Worker\anchor RECOMMENDED
23*fb1b10abSAndroid Build Coastguard Worker   This word, or the adjective "RECOMMENDED", mean that there
24*fb1b10abSAndroid Build Coastguard Worker   may exist valid reasons in particular circumstances to ignore a
25*fb1b10abSAndroid Build Coastguard Worker   particular item, but the full implications must be understood and
26*fb1b10abSAndroid Build Coastguard Worker   carefully weighed before choosing a different course.
27*fb1b10abSAndroid Build Coastguard Worker
28*fb1b10abSAndroid Build Coastguard Worker\section SHOULDNOT SHOULD NOT
29*fb1b10abSAndroid Build Coastguard Worker\anchor NOTRECOMMENDED
30*fb1b10abSAndroid Build Coastguard Worker   This phrase, or the phrase "NOT RECOMMENDED" mean that
31*fb1b10abSAndroid Build Coastguard Worker   there may exist valid reasons in particular circumstances when the
32*fb1b10abSAndroid Build Coastguard Worker   particular behavior is acceptable or even useful, but the full
33*fb1b10abSAndroid Build Coastguard Worker   implications should be understood and the case carefully weighed
34*fb1b10abSAndroid Build Coastguard Worker   before implementing any behavior described with this label.
35*fb1b10abSAndroid Build Coastguard Worker
36*fb1b10abSAndroid Build Coastguard Worker\section MAY
37*fb1b10abSAndroid Build Coastguard Worker\anchor OPTIONAL
38*fb1b10abSAndroid Build Coastguard Worker   This word, or the adjective "OPTIONAL", mean that an item is
39*fb1b10abSAndroid Build Coastguard Worker   truly optional.  One vendor may choose to include the item because a
40*fb1b10abSAndroid Build Coastguard Worker   particular marketplace requires it or because the vendor feels that
41*fb1b10abSAndroid Build Coastguard Worker   it enhances the product while another vendor may omit the same item.
42*fb1b10abSAndroid Build Coastguard Worker   An implementation which does not include a particular option \ref MUST be
43*fb1b10abSAndroid Build Coastguard Worker   prepared to interoperate with another implementation which does
44*fb1b10abSAndroid Build Coastguard Worker   include the option, though perhaps with reduced functionality. In the
45*fb1b10abSAndroid Build Coastguard Worker   same vein an implementation which does include a particular option
46*fb1b10abSAndroid Build Coastguard Worker   \ref MUST be prepared to interoperate with another implementation which
47*fb1b10abSAndroid Build Coastguard Worker   does not include the option (except, of course, for the feature the
48*fb1b10abSAndroid Build Coastguard Worker   option provides.)
49*fb1b10abSAndroid Build Coastguard Worker
50*fb1b10abSAndroid Build Coastguard Worker
51*fb1b10abSAndroid Build Coastguard Worker*/
52