endhostent(3XNET)X/Open Networking Services Library Functionsendhostent(3XNET)NAME
endhostent, gethostbyaddr, gethostbyname, gethostent, sethostent - net‐
work host database functions
SYNOPSIS
cc [ flag ... ] file ... -lxnet [ library ... ]
#include <netdb.h>
extern int h_errno;
void endhostent(void);
struct hostent *gethostbyaddr(const void *addr, socklen_t len, int
type);
struct hostent *gethostbyname(const char *name);
struct hostent *gethostent(void);
void sethostent(int stayopen);
DESCRIPTION
The gethostent(), gethostbyaddr(), and gethostbyname() functions each
return a pointer to a hostent structure, the members of which contain
the fields of an entry in the network host database.
The gethostent() function reads the next entry of the database, opening
a connection to the database if necessary.
The gethostbyaddr() function searches the database and finds an entry
which matches the address family specified by the type argument and
which matches the address pointed to by the addr argument, opening a
connection to the database if necessary. The addr argument is a
pointer to the binary-format (that is, not null-terminated) address in
network byte order, whose length is specified by the len argument. The
datatype of the address depends on the address family. For an address
of type AF_INET, this is an in_addr structure, defined in
<netinet/in.h>. For an address of type AF_INET6, there is an in6_addr
structure defined in <netinet/in.h>.
The gethostbyname() function searches the database and finds an entry
which matches the host name specified by the name argument, opening a
connection to the database if necessary. If name is an alias for a
valid host name,
the function returns information about the host name to which the
alias refers, and name is included in the list of aliases returned.
The sethostent() function opens a connection to the network host data‐
base, and sets the position of the next entry to the first entry. If
the stayopen argument is non-zero, the connection to the host database
will not be closed after each call to gethostent() (either directly, or
indirectly through one of the other gethost*() functions).
The endhostent() function closes the connection to the database.
USAGE
The gethostent(), gethostbyaddr(), and gethostbyname() functions may
return pointers to static data, which may be overwritten by subsequent
calls to any of these functions.
These functions are generally used with the Internet address family.
RETURN VALUES
On successful completion, gethostbyaddr(), gethostbyname() and gethos‐
tent() return a pointer to a hostent structure if the requested entry
was found, and a null pointer if the end of the database was reached or
the requested entry was not found. Otherwise, a null pointer is
returned.
On unsuccessful completion, gethostbyaddr() and gethostbyname() func‐
tions set h_errno to indicate the error.
ERRORS
No errors are defined for endhostent(), gethostent() and sethostent().
The gethostbyaddr() and gethostbyname() functions will fail in the fol‐
lowing cases, setting h_errno to the value shown in the list below.
Any changes to errno are unspecified.
HOST_NOT_FOUND No such host is known.
NO_DATA The server recognised the request and the name
but no address is available. Another type of
request to the name server for the domain might
return an answer.
NO_RECOVERY An unexpected server failure occurred which can
not be recovered.
TRY_AGAIN A temporary and possibly transient error
occurred, such as a failure of a server to
respond.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOendservent(3XNET), htonl(3XNET), inet_addr(3XNET), attributes(5), stan‐
dards(5)SunOS 5.10 1 Nov 2003 endhostent(3XNET)