Socket::GetAddrInfo::EUser3Contributed Perl DocuSocket::GetAddrInfo::Emul(3pm)
NAME
"Socket::GetAddrInfo::Emul" - Pure Perl emulation of "getaddrinfo" and
"getnameinfo" using IPv4-only legacy resolvers
DESCRIPTION
"Socket::GetAddrInfo" attempts to provide the "getaddrinfo" and
"getnameinfo" functions by some XS code that calls the real functions
in libc. If for some reason this cannot be done; either there is no C
compiler, or libc does not provide these functions, then they will be
emulated using the legacy resolvers "gethostbyname", etc... These
emulations are not a complete replacement of the real functions,
because they only support IPv4 (the "AF_INET" socket family). In this
case, the following restrictions will apply.
getaddrinfo
• If the "family" hint is supplied, it must be "AF_INET". Any other
value will result in an error thrown by "croak".
• The only supported "flags" hint values are "AI_PASSIVE",
"AI_CANONNAME", "AI_NUMERICSERV" and "AI_NUMERICHOST".
The flags "AI_V4MAPPED" and "AI_ALL" are recognised but ignored, as
they do not apply to "AF_INET" lookups. Since this function only
returns "AF_INET" addresses, it does not need to probe the system
for configured addresses in other families, so the "AI_ADDRCONFIG"
flag is also ignored.
Note that "AI_NUMERICSERV" is an extension not defined by RFC 2553,
but is provided by most OSes. It is possible (though unlikely) that
even the native XS implementation does not recognise this constant.
getnameinfo
• If the sockaddr family of $addr is anything other than "AF_INET",
an error will be thrown with "croak".
• The only supported $flags values are "NI_NUMERICHOST",
"NI_NUMERICSERV", "NI_NOFQDN", "NI_NAMEREQD" and "NI_DGRAM".
IDN SUPPORT
This pure-perl emulation provides the IDN constants such as "AI_IDN"
and "NI_IDN", but the "getaddrinfo" and "getnameinfo" functions will
croak if passed these flags. This should allow a program to probe for
their support, and fall back to some other behaviour instead.
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.34.0 2022-10-13 Socket::GetAddrInfo::Emul(3pm)
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