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<h4 class="subsection">12.14.7 Other Input Conversions</h4>

<p>This section describes the miscellaneous input conversions.

   <p>The &lsquo;<samp><span class="samp">%p</span></samp>&rsquo; conversion is used to read a pointer value.  It recognizes
the same syntax used by the &lsquo;<samp><span class="samp">%p</span></samp>&rsquo; output conversion for
<code>printf</code> (see <a href="Other-Output-Conversions.html#Other-Output-Conversions">Other Output Conversions</a>); that is, a hexadecimal
number just as the &lsquo;<samp><span class="samp">%x</span></samp>&rsquo; conversion accepts.  The corresponding
argument should be of type <code>void **</code>; that is, the address of a
place to store a pointer.

   <p>The resulting pointer value is not guaranteed to be valid if it was not
originally written during the same program execution that reads it in.

   <p>The &lsquo;<samp><span class="samp">%n</span></samp>&rsquo; conversion produces the number of characters read so far
by this call.  The corresponding argument should be of type <code>int *</code>. 
This conversion works in the same way as the &lsquo;<samp><span class="samp">%n</span></samp>&rsquo; conversion for
<code>printf</code>; see <a href="Other-Output-Conversions.html#Other-Output-Conversions">Other Output Conversions</a>, for an example.

   <p>The &lsquo;<samp><span class="samp">%n</span></samp>&rsquo; conversion is the only mechanism for determining the
success of literal matches or conversions with suppressed assignments. 
If the &lsquo;<samp><span class="samp">%n</span></samp>&rsquo; follows the locus of a matching failure, then no value
is stored for it since <code>scanf</code> returns before processing the
&lsquo;<samp><span class="samp">%n</span></samp>&rsquo;.  If you store <code>-1</code> in that argument slot before calling
<code>scanf</code>, the presence of <code>-1</code> after <code>scanf</code> indicates an
error occurred before the &lsquo;<samp><span class="samp">%n</span></samp>&rsquo; was reached.

   <p>Finally, the &lsquo;<samp><span class="samp">%%</span></samp>&rsquo; conversion matches a literal &lsquo;<samp><span class="samp">%</span></samp>&rsquo; character
in the input stream, without using an argument.  This conversion does
not permit any flags, field width, or type modifier to be specified.

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