gethostbyname man page on DigitalUNIX

Man page or keyword search:  
man Server   12896 pages
apropos Keyword Search (all sections)
Output format
DigitalUNIX logo
[printable version]

gethostbyname(3)					      gethostbyname(3)

       gethostbyname, gethostbyname_r - Get a network host entry by name

       #include <netdb.h>

       struct hostent *gethostbyname(
	       const char *name );

       [Tru64  UNIX]  The following function is supported in order to maintain
       backward compatibility with previous versions of the operating  system.
       You should not use it in new designs.  int gethostbyname_r(
	       const char *name,
	       struct hostent *hptr,
	       struct hostent_data *hdptr );

       Standard C Library (libc)

       Interfaces  documented on this reference page conform to industry stan‐
       dards as follows:

       gethostbyname():	 XNS4.0, XNS5.0

       Refer to the standards(5) reference page	 for  more  information	 about
       industry standards and associated tags.

       Specifies  the official network name or alias.  [Tru64 UNIX]  For geth‐
       ostbyname_r() only, this points to the hostent structure.  The  netdb.h
       header  file  defines  hostent structure.  [Tru64 UNIX]	For gethostby‐
       name_r() only, this is data for hosts  database.	  The  netdb.h	header
       file defines hostent_data structure.

       The  gethostbyname()  function returns a pointer to a structure of type
       hostent.	 Its members specify  data  obtained  from  either  the	 local
       /etc/hosts  file or one of the files distributed by DNS/BIND or NIS. To
       determine which file or files to search, and in which order, the system
       uses  the  switches in the /etc/svc.conf file.  The netdb.h header file
       defines the hostent structure.

       If using DNS/BIND, the information is obtained from a name server spec‐
       ified in the /etc/resolv.conf file.

       If  the	name  parameter	 does  not contain a dot "." and you are using
       DNS/BIND, the gethostbyname() function checks whether  the  environment
       variable	 HOSTALIASES is set.  If set, it first searches the file named
       by HOSTALIASES for an alias matching the	 name  parameter.   The	 alias
       file has the following format:

       name1 name2

       The  alias name.	 This name cannot include dots.	 The host name used by
       DNS/BIND to look up the host information.  The hosts database  must  be
       distributed by DNS/BIND.

       The gethostbyname() function returns a pointer to thread-specific data.
       Subsequent calls to this or a related function  from  the  same	thread
       overwrite this data.

       [Tru64  UNIX]  The  gethostbyname_r() function is an obsolete reentrant
       version of the gethostbyname() function.	 It is supported in  order  to
       maintain backward compatibility with previous versions of the operating
       system and should not be used in new designs.  Note that you must zero-
       fill  the  hdptr	 structure  before  its first access by the gethostby‐
       name_r() function.

       Upon successful completion,  the	 gethostbyname()  function  returns  a
       pointer	to  a hostent structure.  If it reaches the end of the network
       host name database, it returns a null pointer.

       [Tru64 UNIX]  Upon successful completion, the  gethostbyname_r()	 func‐
       tion  stores  the hostent structure in the location pointed to by hptr,
       and returns a value of 0 (zero). Upon failure, it returns  a  value  of

       If  the	gethostbyname()	 or  gethostbyname_r()	function  call	fails,
       h_errno is set to one of the following the  values:  Host  is  unknown.
       The  server  recognized	the  request  and  the name, but no address is
       available for the name.	Another type of name  server  request  may  be
       successful.   An	 unexpected server failure occurred.  This is a nonre‐
       coverable error.	 A transient error occurred, for example,  the	server
       did not respond.	 A retry at some later time may be successful.

       [Tru64  UNIX]  If  any of the following conditions occurs, the gethost‐
       byaddr_r() function sets errno to the corresponding  value:  The	 name,
       hptr, or hdptr is invalid.

       The  Internet network host name database. Each record in the file occu‐
       pies a single line and has three fields consisting of the host address,
       official host name, and aliases.	 The resolver configuration file.  The
       database service selection configuration file.

       Functions: endhostent(3), gethostbyaddr(3), sethostent(3).

       Files: hostname(5), resolv.conf(4), svc.conf(4).

       Networks: bind_intro(7), nis_intro(7).

       Standards: standards(5)

       Network Programmer's Guide


List of man pages available for DigitalUNIX

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
Vote for polarhome
Free Shell Accounts :: the biggest list on the net