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<pre>
<span class="headline">STRNCPY(3P)               POSIX Programmer's Manual              STRNCPY(3P)</span>
</pre>
<h2><a id="PROLOG" href="strncpy.3p.html#PROLOG"></a>PROLOG  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       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.
</pre>
<h2><a id="NAME" href="strncpy.3p.html#NAME"></a>NAME  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       stpncpy, strncpy — copy fixed length string, returning a pointer to
       the array end
</pre>
<h2><a id="SYNOPSIS" href="strncpy.3p.html#SYNOPSIS"></a>SYNOPSIS  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       #include &lt;string.h&gt;

       char *stpncpy(char *restrict <i>s1</i>, const char *restrict <i>s2</i>, size_t <i>n</i>);
       char *strncpy(char *restrict <i>s1</i>, const char *restrict <i>s2</i>, size_t <i>n</i>);
</pre>
<h2><a id="DESCRIPTION" href="strncpy.3p.html#DESCRIPTION"></a>DESCRIPTION  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       For <i>strncpy</i>(): The functionality described on this reference page is
       aligned with the ISO C standard. Any conflict between the
       requirements described here and the ISO C standard is unintentional.
       This volume of POSIX.1‐2008 defers to the ISO C standard.

       The <i>stpncpy</i>() and <i>strncpy</i>() functions shall copy not more than <i>n</i>
       bytes (bytes that follow a NUL character are not copied) from the
       array pointed to by <i>s2</i> to the array pointed to by <i>s1</i>.

       If the array pointed to by <i>s2</i> is a string that is shorter than <i>n</i>
       bytes, NUL characters shall be appended to the copy in the array
       pointed to by <i>s1</i>, until <i>n</i> bytes in all are written.

       If copying takes place between objects that overlap, the behavior is
       undefined.
</pre>
<h2><a id="RETURN_VALUE" href="strncpy.3p.html#RETURN_VALUE"></a>RETURN VALUE  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       If a NUL character is written to the destination, the <i>stpncpy</i>()
       function shall return the address of the first such NUL character.
       Otherwise, it shall return <i>&amp;s1</i>[<i>n</i>].

       The <i>strncpy</i>() function shall return <i>s1</i>.

       No return values are reserved to indicate an error.
</pre>
<h2><a id="ERRORS" href="strncpy.3p.html#ERRORS"></a>ERRORS  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       No errors are defined.

       <i>The following sections are informative.</i>
</pre>
<h2><a id="EXAMPLES" href="strncpy.3p.html#EXAMPLES"></a>EXAMPLES  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       None.
</pre>
<h2><a id="APPLICATION_USAGE" href="strncpy.3p.html#APPLICATION_USAGE"></a>APPLICATION USAGE  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       Applications must provide the space in <i>s1</i> for the <i>n</i> bytes to be
       transferred, as well as ensure that the <i>s2</i> and <i>s1</i> arrays do not
       overlap.

       Character movement is performed differently in different
       implementations. Thus, overlapping moves may yield surprises.

       If there is no NUL character byte in the first <i>n</i> bytes of the array
       pointed to by <i>s2</i>, the result is not null-terminated.
</pre>
<h2><a id="RATIONALE" href="strncpy.3p.html#RATIONALE"></a>RATIONALE  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       None.
</pre>
<h2><a id="FUTURE_DIRECTIONS" href="strncpy.3p.html#FUTURE_DIRECTIONS"></a>FUTURE DIRECTIONS  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       None.
</pre>
<h2><a id="SEE_ALSO" href="strncpy.3p.html#SEE_ALSO"></a>SEE ALSO  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       <a href="strcpy.3p.html">strcpy(3p)</a>, <a href="wcsncpy.3p.html">wcsncpy(3p)</a>

       The Base Definitions volume of POSIX.1‐2008, <a href="../man0/string.h.0p.html">string.h(0p)</a>
</pre>
<h2><a id="COPYRIGHT" href="strncpy.3p.html#COPYRIGHT"></a>COPYRIGHT  &nbsp; &nbsp; &nbsp; &nbsp; <a href="strncpy.3p.html#top_of_page"><span class="top-link">top</span></a></h2><pre>
       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 <a href="http://www.unix.org/online.html">http://www.unix.org/online.html</a> .

       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
       <a href="https://www.kernel.org/doc/man-pages/reporting_bugs.html">https://www.kernel.org/doc/man-pages/reporting_bugs.html</a> .

<span class="footline">IEEE/The Open Group                 2013                         STRNCPY(3P)</span>
</pre>

<hr class="end-man-text" />
<p>Pages that refer to this page: 
    <a href="../man0/string.h.0p.html">string.h(0p)</a>,&nbsp; 
    <a href="stpncpy.3p.html">stpncpy(3p)</a>,&nbsp; 
    <a href="strcpy.3p.html">strcpy(3p)</a>,&nbsp; 
    <a href="wcsncpy.3p.html">wcsncpy(3p)</a>
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