NAME    [Toc]    [Back]

       gethostent,  gethostent_r, sethostent, sethostent_r - Open
       a network host file

SYNOPSIS    [Toc]    [Back]

       #include <netdb.h>

       struct hostent *gethostent(
               void ); void sethostent(
               int stay_open );

       [Tru64 UNIX]  The following obsolete  functions  are  supported
  in  order  to maintain backward compatibility with
       previous versions of the operating system.  You should not
       use them in new designs.  int gethostent_r(
               struct hostent *host,
               struct  hostent_data  *host_data  );  int  sethostent_r(

               int stay_open,
               struct hostent_data *host_data );

       [Tru64 UNIX]  The following definition of the sethostent()
       function does not conform to current standards and is supported
 only for backward compatibility: int sethostent(
               int stay_open );

LIBRARY    [Toc]    [Back]

       Standard C Library (libc)

STANDARDS    [Toc]    [Back]

       Interfaces documented on this reference  page  conform  to
       industry standards as follows:

       gethostent():  XNS4.0, XNS5.0

       sethostent():  XNS4.0, XNS5.0

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

PARAMETERS    [Toc]    [Back]

       [Tru64 UNIX]  For gethostent_r() only, this points to  the
       hostent  structure.    The netdb.h header file defines the
       hostent structure.  [Tru64 UNIX]  For  gethostent_r()  and
       sethostent_r()  only,  this is data for the host database.
       The netdb.h header file defines  the  hostent_data  structure.
  Contains a value used to indicate when to close the
       network host database. Specifying  a  value  of  0  (zero)
       closes  the  network host database file after each call to
       the gethostbyname() or gethostbyaddr() function.  Specifying
  a nonzero value allows the network host database file
       to remain open after each call.

DESCRIPTION    [Toc]    [Back]

       The gethostent() (get host entry) function reads the  next
       line of the either the local /etc/hosts file or one of the
       files distributed by BIND or NIS, opening it if necessary,
       returning  a  hostent  structure.  The netdb.h header file
       defines the hostent_data structure.

       The sethostent() (set host entry)  function  opens  either
       the  local /etc/hosts file or one of the files distributed
       by BIND or NIS, and resets the file marker to  the  beginning
  of  the  file.   To determine which file or files to
       search, and in which order, the system uses  the  switches
       in the /etc/svc.conf file.

       Passing  a nonzero value to the stay_open parameter establishes
 a connection with a name server and allows a client
       process  to  retrieve one entry at a time from the network
       hosts database file.  The client  process  can  close  the
       connection with the endhostent() function.

NOTES    [Toc]    [Back]

       The gethostent() 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 gethostent_r() and sethostent_r() functions
 are obsolete reentrant versions of the  gethostent()
       and  sethostent()  functions.  They are 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  host_data
       structure  before  its  first access by the gethostent_r()
       function.

RETURN VALUES    [Toc]    [Back]

       Upon  successful  completion,  the  gethostent()  function
       returns  a pointer to a hostent structure.  If it fails or
       reaches the end of the  network  hostname  database,   the
       gethostent() function returns a null pointer and places an
       appropriate error code in the h_errno variable.

       [Tru64  UNIX]  Upon  successful  completion,  the  gethostent_r()
  and sethostent_r() functions return a value of 0
       (zero).  The gethostent_r() function  stores  the  hostent
       data  structure  in the location pointed to by host.  Upon
       failure, the gethostent_r() and  sethostent_r()  functions
       return a value of -1 and set the errno variable.

       [Tru64  UNIX]  The  version  of  sethostent() that is supported
 for backward compatibility always returns  a  value
       of 1.

ERRORS    [Toc]    [Back]

       Current  industry standards do not define error values for
       the gethostent() and sethostent() functions.

       [Tru64 UNIX]  If the following condition occurs, the gethostent()
  or  gethostent_r()  function sets h_errno to the
       corresponding value: This error code indicates an unrecoverable
 error.

       [Tru64 UNIX]  If the following condition occurs, the gethostent_r()
 function sets errno to the corresponding value:
       The host or host_data parameter is invalid.

       [Tru64  UNIX]  If  the  following  condition  occurs,  the
       sethostent_r() function sets errno  to  the  corresponding
       value: The host_data parameter is invalid.

       [Tru64 UNIX]  In addition, the sethostent(), backward compatible
 version of sethostent() and  sethostent_r()  functions
  can fail to open the file.  In this case errno will
       be set to the failure.

FILES    [Toc]    [Back]

       Contains the hostname database.  Contains the name  server
       and  domain name.  The database service selection configuration
 file.

SEE ALSO    [Toc]    [Back]

       Functions:  endhostent(3),  gethostbyaddr(3),   gethostbyname(3)

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

       Networks: bind_intro(7), nis_intro(7)

       Standards: standards(5)

       Network Programmer's Guide



                                                    gethostent(3)