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.
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
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.
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().
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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.unix.org/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
IEEE/The Open Group 2013 ENDHOSTENT(3P)