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<H1>INET_NTOP</H1>
Section: Linux Programmer's Manual (3)<BR>Updated: 2017-09-15<BR><A HREF="#index">Index</A>
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>
inet_ntop - convert IPv4 and IPv6 addresses from binary to text form
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<PRE>
<B>#include &lt;<A HREF="file:///usr/include/arpa/inet.h">arpa/inet.h</A>&gt;</B>
<B>const char *inet_ntop(int </B><I>af</I><B>, const void *</B><I>src</I><B>,</B>
<B> char *</B><I>dst</I><B>, socklen_t </B><I>size</I><B>);</B>
</PRE>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
This function converts the network address structure
<I>src</I>
in the
<I>af</I>
address family into a character string.
The resulting string is copied to the buffer pointed to by
<I>dst</I>,
which must be a non-null pointer.
The caller specifies the number of bytes available in this buffer in
the argument
<I>size</I>.
<P>
<B>inet_ntop</B>()
extends the
<B><A HREF="/cgi-bin/man/man2html?3+inet_ntoa">inet_ntoa</A></B>(3)
function to support multiple address families,
<B><A HREF="/cgi-bin/man/man2html?3+inet_ntoa">inet_ntoa</A></B>(3)
is now considered to be deprecated in favor of
<B>inet_ntop</B>().
The following address families are currently supported:
<DL COMPACT>
<DT id="1"><B>AF_INET</B>
<DD>
<I>src</I>
points to a
<I>struct in_addr</I>
(in network byte order)
which is converted to an IPv4 network address in
the dotted-decimal format, &quot;<I>ddd.ddd.ddd.ddd</I>&quot;.
The buffer
<I>dst</I>
must be at least
<B>INET_ADDRSTRLEN</B>
bytes long.
<DT id="2"><B>AF_INET6</B>
<DD>
<I>src</I>
points to a
<I>struct in6_addr</I>
(in network byte order)
which is converted to a representation of this address in the
most appropriate IPv6 network address format for this address.
The buffer
<I>dst</I>
must be at least
<B>INET6_ADDRSTRLEN</B>
bytes long.
</DL>
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
On success,
<B>inet_ntop</B>()
returns a non-null pointer to
<I>dst</I>.
NULL is returned if there was an error, with
<I>errno</I>
set to indicate the error.
<A NAME="lbAF">&nbsp;</A>
<H2>ERRORS</H2>
<DL COMPACT>
<DT id="3"><B>EAFNOSUPPORT</B>
<DD>
<I>af</I>
was not a valid address family.
<DT id="4"><B>ENOSPC</B>
<DD>
The converted address string would exceed the size given by
<I>size</I>.
</DL>
<A NAME="lbAG">&nbsp;</A>
<H2>ATTRIBUTES</H2>
For an explanation of the terms used in this section, see
<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
<TABLE BORDER>
<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
<TR VALIGN=top><TD>
<B>inet_ntop</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe locale<BR></TD></TR>
</TABLE>
<P>
<A NAME="lbAH">&nbsp;</A>
<H2>CONFORMING TO</H2>
POSIX.1-2001, POSIX.1-2008.
Note that RFC&nbsp;2553 defines a prototype where the last argument
<I>size</I>
is of type
<I>size_t</I>.
Many systems follow RFC&nbsp;2553.
Glibc 2.0 and 2.1 have
<I>size_t</I>,
but 2.2 and later have
<I>socklen_t</I>.
<A NAME="lbAI">&nbsp;</A>
<H2>BUGS</H2>
<B>AF_INET6</B>
converts IPv4-mapped IPv6 addresses into an IPv6 format.
<A NAME="lbAJ">&nbsp;</A>
<H2>EXAMPLE</H2>
See
<B><A HREF="/cgi-bin/man/man2html?3+inet_pton">inet_pton</A></B>(3).
<A NAME="lbAK">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?3+getnameinfo">getnameinfo</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+inet">inet</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+inet_pton">inet_pton</A></B>(3)
<A NAME="lbAL">&nbsp;</A>
<H2>COLOPHON</H2>
This page is part of release 5.05 of the Linux
<I>man-pages</I>
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
<P>
<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT id="5"><A HREF="#lbAB">NAME</A><DD>
<DT id="6"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="7"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="8"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DT id="9"><A HREF="#lbAF">ERRORS</A><DD>
<DT id="10"><A HREF="#lbAG">ATTRIBUTES</A><DD>
<DT id="11"><A HREF="#lbAH">CONFORMING TO</A><DD>
<DT id="12"><A HREF="#lbAI">BUGS</A><DD>
<DT id="13"><A HREF="#lbAJ">EXAMPLE</A><DD>
<DT id="14"><A HREF="#lbAK">SEE ALSO</A><DD>
<DT id="15"><A HREF="#lbAL">COLOPHON</A><DD>
</DL>
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