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NAME |LIBRARY |SYNOPSIS |DESCRIPTION |RETURN VALUE |STANDARDS |HISTORY |SEE ALSO |COLOPHON | |
getipnodebyname(3) Library Functions Manualgetipnodebyname(3)getipnodebyname, getipnodebyaddr, freehostent - get network hostnames and addresses
Standard C library (libc,-lc)
#include <sys/types.h>#include <sys/socket.h>#include <netdb.h>[[deprecated]] struct hostent *getipnodebyname(const char *name, intaf,intflags, int *error_num);[[deprecated]] struct hostent *getipnodebyaddr(size_t size;const voidaddr[size],size_tsize, intaf,int *error_num);[[deprecated]] void freehostent(struct hostent *ip);
These functions are deprecated (and unavailable in glibc). Usegetaddrinfo(3) andgetnameinfo(3) instead. Thegetipnodebyname() andgetipnodebyaddr() functions return the names and addresses of a network host. These functions return a pointer to the following structure: struct hostent { char *h_name; char **h_aliases; int h_addrtype; int h_length; char **h_addr_list; }; These functions replace thegethostbyname(3) andgethostbyaddr(3) functions, which could access only the IPv4 network address family. Thegetipnodebyname() andgetipnodebyaddr() functions can access multiple network address families. Unlike thegethostbyfunctions, these functions return pointers to dynamically allocated memory. Thefreehostent() function is used to release the dynamically allocated memory after the caller no longer needs thehostent structure.getipnodebyname() arguments Thegetipnodebyname() function looks up network addresses for the host specified by thename argument. Theaf argument specifies one of the following values:AF_INET Thename argument points to a dotted-quad IPv4 address or a name of an IPv4 network host.AF_INET6 Thename argument points to a hexadecimal IPv6 address or a name of an IPv6 network host. Theflags argument specifies additional options. More than one option can be specified by bitwise OR-ing them together.flags should be set to 0 if no options are desired.AI_V4MAPPED This flag is used withAF_INET6to request a query for IPv4 addresses instead of IPv6 addresses; the IPv4 addresses will be mapped to IPv6 addresses.AI_ALLThis flag is used withAI_V4MAPPEDto request a query for both IPv4 and IPv6 addresses. Any IPv4 address found will be mapped to an IPv6 address.AI_ADDRCONFIG This flag is used withAF_INET6to further request that queries for IPv6 addresses should not be made unless the system has at least one IPv6 address assigned to a network interface, and that queries for IPv4 addresses should not be made unless the system has at least one IPv4 address assigned to a network interface. This flag may be used by itself or with theAI_V4MAPPEDflag.AI_DEFAULT This flag is equivalent to(AI_ADDRCONFIG | AI_V4MAPPED).getipnodebyaddr() arguments Thegetipnodebyaddr() function looks up the name of the host whose network address is specified by theaddr argument. Theaf argument specifies one of the following values:AF_INET Theaddr argument points to astruct in_addr andsize must be set tosizeof(struct in_addr).AF_INET6 Theaddr argument points to astruct in6_addr andsize must be set tosizeof(struct in6_addr).NULL is returned if an error occurred, anderror_num will contain an error code from the following list:HOST_NOT_FOUND The hostname or network address was not found.NO_ADDRESS The domain name server recognized the network address or name, but no answer was returned. This can happen if the network host has only IPv4 addresses and a request has been made for IPv6 information only, or vice versa.NO_RECOVERY The domain name server returned a permanent failure response.TRY_AGAIN The domain name server returned a temporary failure response. You might have better luck next time. A successful query returns a pointer to ahostent structure that contains the following fields:h_name This is the official name of this network host.h_aliases This is an array of pointers to unofficial aliases for the same host. The array is terminated by a null pointer.h_addrtype This is a copy of theaf argument togetipnodebyname() orgetipnodebyaddr().h_addrtype will always beAF_INETif theaf argument wasAF_INET.h_addrtype will always beAF_INET6if theaf argument wasAF_INET6.h_length This field will be set tosizeof(struct in_addr) ifh_addrtype isAF_INET, and tosizeof(struct in6_addr) ifh_addrtype isAF_INET6.h_addr_list This is an array of one or more pointers to network address structures for the network host. The array is terminated by a null pointer.
None.
RFC 2553. Present in glibc 2.1.91-95, but removed again. Several UNIX-like systems support them, but all call them deprecated.
getaddrinfo(3),getnameinfo(3),inet_ntop(3),inet_pton(3)
This page is part of theman-pages (Linux kernel and C library user-space interface documentation) project. Information about the project can be found at ⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report for this manual page, see ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩. This page was obtained from the tarball man-pages-6.15.tar.gz fetched from ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on 2025-08-11. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up- to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which isnot part of the original manual page), send a mail to man-pages@man7.orgLinux man-pages 6.15 2025-06-28getipnodebyname(3)HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |