.\" This page is in the public domain.
.\" Almost all details are from RFC 2553.
.\"
.\" 2004-12-14, mtk, Added EAI_OVERFLOW error
.\" 2004-12-14 Fixed description of error return
.\"
.\" Translated 2005-02-26, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2007-01-07, Akihiro MOTOKI, LDP v2.43
.\" Updated 2008-08-11, Akihiro MOTOKI, LDP v3.05
.\"
.TH GETNAMEINFO 3 2009-02-23 "GNU" "Linux Programmer's Manual"
.SH ̾
getnameinfo \- ɥ쥹̾ؤѴץȥ˰¸ʤǹԤ
.SH 
.nf
.B #include <sys/socket.h>
.B #include <netdb.h>
.sp
.BI "int getnameinfo(const struct sockaddr *" "sa" ", socklen_t " "salen" ,
.BI "                char *" "host" ", size_t " "hostlen" ,
.BI "                char *" "serv" ", size_t " "servlen" ", int " "flags" );
.fi
.sp
.in -4n
glibc εǽޥ׷
.RB ( feature_test_macros (7)
):
.ad l
.in
.sp
.BR getnameinfo ():
_POSIX_C_SOURCE\ >=\ 1 || _XOPEN_SOURCE || _POSIX_SOURCE
.ad b
.SH 
.BR getnameinfo ()
ؿϡ
.BR getaddrinfo (3)
εդưԤĤޤꡢץȥ˰¸ʤ
åȥɥ쥹бۥ̾ȥӥؤѴԤ
δؿ
.BR gethostbyaddr (3)

.BR getservbyport (3)
εǽĤˤΤ
δؿȰ㤤
.BR getnameinfo (3)
ϥꥨȥȤǤꡢIPv4  IPv6 κʬ˰¸ʤ
ץ񤯤ȤǤ롣

.I sa
ϡ
IP ɥ쥹ȥݡֹξݻƤ
Ūʥåȥɥ쥹¤
.RI ( sockaddr_in
ޤ
.I sockaddr_in6
) ؤΥݥ󥿤Ǥ롣
.I salen

.I sa
ΥǤ롣
.I host

.I serv
ϡ(줾쥵
.I hostlen

.I servlen
) ƤӽФ¦dzݤ줿ХåեؤΥݥ󥿤Ǥꡢ
ۥ̾ȥӥ̾ޤ NULL ü줿ʸ
줾ΥХåե˳Ǽ롣

ۥ̾פǤ뤳Ȥ򤳤δؿˤϡ
.I host
 NULL ꤹ뤫
.I hostlen
 0 ꤹ롣Ʊͤˡӥ̾פʾϡ
.I serv
 NULL ꤹ뤫
.I servlen
 0 ꤹ롣
ۥ̾ȥӥ̾ξפȻꤹ뤳ȤϤǤʤ
(줫׵᤹뤳)

.I flags

.BR getnameinfo ()
ưѤ뤳ȤǤ롣Ǥͤϰʲ̤:
.TP
.B NI_NAMEREQD
ꤹȡۥ̾Ǥʤä˥顼֤
.TP
.B NI_DGRAM
ꤹȡȥ꡼١ (TCP) Ǥʤǡ١ (UDP)
Υӥоݤˤ롣Ͼʤ
UDP  TCP ǰ㤦ӥ󶡤Ƥݡ
(512-514) ФɬפȤʤ롣
.TP
.B NI_NOFQDN
ꤹȡʥۥȤˤ fully qualified domain name (FQDN) 
ۥ̾ʬΤߤ֤
.TP
.B NI_NUMERICHOST
ꤹȡͷΥۥ֤̾롣
.\" 㤨
.\" .BR gethostbyaddr ()
.\" 
.\" .BR inet_ntop ()
.\" Ƥ
(ꤷʤƤ⡢Ρɤ̾ǤʤϿͷ֤뤳Ȥ)
.\" POSIX.1-2003 has NI_NUMERICSCOPE, but glibc doesn't have it.
.TP
.B NI_NUMERICSERV
ꤹȡͷΥӥ̾ (㤨Хݡֹ) ֤
(ꤷʤƤ⡢ӥ̾ǤʤϿͷ֤뤳Ȥ)
.SS "ݲɥᥤ̾Τ getnameinfo() γĥ"
.PP
glibc 2.3.4 顢
.BR getnameinfo ()
˳ĥԤ졢ۥ̾
ݲɥᥤ̾ (Internationalized Domain Name; IDN) Ȥδ֤
ƩŪѴǤ褦ˤʤäƤ
(IDN ˤĤƤ RFC 3490 
.I "Internationalizing Domain Names in Applications (IDNA)"
򻲾)3ĤΥե饰Ƥ:
.TP
.B NI_IDN
Υե饰ꤹȡɬפǤСǸĤä̾
IDN ˱沽Ѵ롣
ASCII ʸ̾ϤѴǤϱƶʤΤᡢ
¸ΥץĶǤΥե饰ȤȤǤ롣
.TP
.BR NI_IDN_ALLOW_UNASSIGNED ", " NI_IDN_USE_STD3_ASCII_RULES
Υե饰򥻥åȤȡIDNA ǻѤե饰
IDNA_ALLOW_UNASSIGNED (̤Ƥ Unicode ΥɥݥȤ) 
IDNA_USE_STD3_ASCII_RULES (Ϥ STD3 Υۥ̾å)
줾ͭˤʤ롣
.SH ֤
.\" FIXME glibc defines the following additional errors, some which
.\" can probably be returned by getnameinfo(); they need to
.\" be documented.
.\" #ifdef __USE_GNU
.\" #define EAI_INPROGRESS  -100  /* Processing request in progress.  */
.\" #define EAI_CANCELED    -101  /* Request canceled.  */
.\" #define EAI_NOTCANCELED -102  /* Request not canceled.  */
.\" #define EAI_ALLDONE     -103  /* All requests done.  */
.\" #define EAI_INTR        -104  /* Interrupted by a signal.  */
.\" #define EAI_IDN_ENCODE  -105  /* IDN encoding failed.  */
.\" #endif
 0 ֤ꡢ(׵ᤵƤ) Ρɤȥӥ̾
NULL ü줿ʸηǤ줾λХåե֤
(ХåեĹˤ褦˽̤뤫⤷ʤ)
顼ξϡʲ 0 ʳΥ顼ɤ֤:
.TP
.B EAI_AGAIN
ꤵ줿̾ǤϲǤʤä
ǺƻԤƤߤ뤳ȡ
.TP
.B EAI_BADFLAGS
.I flags
ͤͿ줿
.TP
.B EAI_FAIL
Ǥʤ顼ȯ
.TP
.B EAI_FAMILY
ꤷɥ쥹եߥ꡼ǧǤʤä
뤤ϥɥ쥹Ĺꤵ줿եߥ꡼˹礦ΤǤʤä
.TP
.B EAI_MEMORY
꤬­ʤ
.TP
.B EAI_NONAME
Ϳ줿ѥ᡼Ǥ̾Ǥʤ
.B NI_NAMEREQD
ꤵƤۥ̾Ǥʤä
ۥ̾⥵ӥ̾׵ᤵʤä
.TP
.B EAI_OVERFLOW
.I host
ޤ
.I serv
ؤƤХåե
.TP
.B EAI_SYSTEM
ƥ२顼ä
顼ɤ
.I errno
ꤵ롣
.PP
.BR gai_strerror (3)
ؿȤȡΥ顼ɤ򡢥顼ݡȤŬ
ʹ֤ɤߤ䤹ʸƤ롣
.SH ե
/etc/hosts
.br
/etc/nsswitch.conf
.br
/etc/resolv.conf
.SH С
.BR getnameinfo ()
ϡglibc С 2.1 ʹߤ󶡤Ƥ롣
.SH 
RFC\ 2553, POSIX.1-2001.
.SH 
ŬڤʥХåեǤ褦ˡ
.I <netdb.h>
˰ʲƤ롣
.in +4n
.nf

#define NI_MAXHOST      1025
#define NI_MAXSERV      32
.fi
.in
.PP
ԤϡǶΥС BIND Υإåե
.I <arpa/nameser.h>

.B MAXDNAME
ƱͤǤ롣
ԤϡƺѤοͤˤĤƵߤ RFC 
󤵤ƥӥ̤ͤǤ롣
.SH 
ʲΥɤϡꤵ줿åȥɥ쥹Ф
ۥȤȥӥοɽ褦Ȼߤ롣
Υɥ쥹եߥ꡼Ф뻲Ⱦ
ڥϡɥɤƤʤȤܤƤۤ

.in +4n
.nf
struct sockaddr *sa;    /* input */
socklen_t len;          /* input */
char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];

if (getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf,
            sizeof(sbuf), NI_NUMERICHOST | NI_NUMERICSERV) == 0)
    printf("host=%s, serv=%s\en", hbuf, sbuf);
.fi
.in

ʲǤϥåȥɥ쥹
ոΥɥ쥹ޥåԥ󥰤¸ߤ뤫åƤ롣

.in +4n
.nf
struct sockaddr *sa;    /* input */
socklen_t len;          /* input */
char hbuf[NI_MAXHOST];

if (getnameinfo(sa, len, hbuf, sizeof(hbuf),
            NULL, 0, NI_NAMEREQD))
    printf("could not resolve hostname");
else
    printf("host=%s\en", hbuf);
.fi
.in
.PP
.BR getnameinfo ()
Ȥäץ㤬
.BR getaddrinfo (3)
˵ܤƤ롣
.SH Ϣ
.BR accept (2),
.BR getpeername (2),
.BR getsockname (2),
.BR recvfrom (2),
.BR socket (2),
.BR getaddrinfo (3),
.BR gethostbyaddr (3),
.BR getservbyname (3),
.BR getservbyport (3),
.BR inet_ntop (3),
.BR hosts (5),
.BR services (5),
.BR hostname (7),
.BR named (8)
.LP
R. Gilligan, S. Thomson, J. Bound and W. Stevens,
.IR "Basic Socket Interface Extensions for IPv6" ,
RFC\ 2553, March 1999.
.LP
Tatsuya Jinmei and Atsushi Onoe,
.IR "An Extension of Format for IPv6 Scoped Addresses" ,
internet draft, work in progress.
ftp://ftp.ietf.org/internet\-drafts/draft\-ietf\-ipngwg\-scopedaddr\-format\-02.txt
.LP
Craig Metz,
.IR "Protocol Independence Using the Sockets API" ,
Proceedings of the freenix track:
2000 USENIX annual technical conference, June 2000.
http://www.usenix.org/publications/library/proceedings/usenix2000/freenix/metzprotocol.html