PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

NAME

       endhostent, gethostent, sethostent — network host database functions

SYNOPSIS

       #include <netdb.h>

       void endhostent(void);
       struct hostent *gethostent(void);
       void sethostent(int stayopen);

DESCRIPTION

       These  functions shall retrieve information about hosts. This information is considered to
       be stored in a database that can be accessed sequentially or randomly. The  implementation
       of this database is unspecified.

       Note:     In  many  cases  this  database  is  implemented  by  the Domain Name System, as
                 documented in RFC 1034, RFC 1035, and RFC 1886.

       The sethostent() function shall open a connection to the database and set the  next  entry
       for  retrieval  to  the first entry in the database. If the stayopen argument is non-zero,
       the connection shall not be closed by a call to gethostent(), and the  implementation  may
       maintain an open file descriptor.

       The gethostent() function shall read the next entry in the database, opening and closing a
       connection to the database as necessary.

       Entries shall be returned in hostent structures.

       The endhostent() function shall close the connection to the database, releasing  any  open
       file descriptor.

       These functions need not be thread-safe.

RETURN VALUE

       Upon  successful completion, the gethostent() function shall 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.

       The  application  shall not modify the structure to which the return value points, nor any
       storage areas pointed to by pointers within  the  structure.  The  returned  pointer,  and
       pointers  within the structure, might be invalidated or the structure or the storage areas
       might be overwritten by a subsequent call to  gethostent().   The  returned  pointer,  and
       pointers  within  the  structure,  might  also  be  invalidated  if  the calling thread is
       terminated.

ERRORS

       No errors are defined for endhostent(), gethostent(), and sethostent().

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       endservent()

       The Base Definitions volume of POSIX.1‐2017, <netdb.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1-2017,  Standard  for  Information Technology -- Portable Operating System Interface
       (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C)  2018  by
       the  Institute  of  Electrical  and Electronics Engineers, Inc and The Open Group.  In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are most  likely  to  have
       been  introduced  during  the conversion of the source files to man page format. To report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .