Defect report from : Kenneth Raeburn , MIT
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@ page 0 line 0 section getaddrinfo comment {none}
Problem:
Defect code : 3. Clarification required
The description of getaddrinfo's AI_CANONNAME flag uses the terms
"canonical name" and "alias" without definition. Since DNS is not
the only possible implementation, it cannot be assumed that the RFC2181
definitions apply in the general case, and it's unclear whether they
should be applied when DNS is used or if that would conflict with some
existing but poorly described notion of what they should mean across
all implementations.
It also gives no indication what the expected behavior is if
AI_CANONNAME is used with a numeric host address string.
Action:
After the second paragraph in the Description section (sorry, I'm
reading the HTML version from opengroup.org, so no line numbers), add
in smaller type this note copied from the gethostbyname description:
Note: In many cases it is implemented by the Domain Name System,
as documented in RFC 1034, RFC 1035, and RFC 1886.
After the Description paragraph starting "If the AI_CANONNAME flag",
add in smaller type:
Note: Since different implementations use different conceptual
models, the terms "canonical name" and "alias" cannot be precisely
defined for the general case. However, Domain Name System
implementations are expected to interpret them as they are used in
RFC 1034.
Note: A numeric host address string is not a "name", and thus
does not have a "canonical name" form; no address to hostname
translation is performed. See below for handling of the case where
a canonical name cannot be obtained.
OR, in place of the second paragraph, depending on the intent:
Note: A numeric host address string is not a "name", and thus
does not have a "canonical name" form. However, implementations
may return the hostname corresponding to the address, as would
be translated by getnameinfo, if it is available.
Add to the Application Usage section:
The term "canonical name" can be misleading. It should be noted
that the canonical name is a result of alias processing, and not
necessarily a unique attribute of a host, address, or set of
addresses. See RFC 2181 for more discussion of this in the Domain
Name System context.
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