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<title>The GNU Fortran Compiler: C_LOC</title>

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<a name="C_005fLOC-_002d_002d_002d-Obtain-the-C-address-of-an-object"></a>
<h3 class="section">9.56 <code>C_LOC</code> &mdash; Obtain the C address of an object</h3>
<a name="index-C_005fLOC"></a>
<a name="index-procedure-pointer_002c-convert-C-to-Fortran"></a>

<dl compact="compact">
<dt><em>Description</em>:</dt>
<dd><p><code>C_LOC(X)</code> determines the C address of the argument.
</p>
</dd>
<dt><em>Standard</em>:</dt>
<dd><p>Fortran 2003 and later
</p>
</dd>
<dt><em>Class</em>:</dt>
<dd><p>Inquiry function
</p>
</dd>
<dt><em>Syntax</em>:</dt>
<dd><p><code>RESULT = C_LOC(X)</code>
</p>
</dd>
<dt><em>Arguments</em>:</dt>
<dd><table>
<tr><td width="10%"><var>X</var></td><td width="75%">Shall have either the POINTER or TARGET attribute. It shall not be a coindexed object. It shall either be a variable with interoperable type and kind type parameters, or be a scalar, nonpolymorphic variable with no length type parameters.</td></tr>
</table>

</dd>
<dt><em>Return value</em>:</dt>
<dd><p>The return value is of type <code>C_PTR</code> and contains the C address
of the argument.
</p>
</dd>
<dt><em>Example</em>:</dt>
<dd><div class="smallexample">
<pre class="smallexample">subroutine association_test(a,b)
  use iso_c_binding, only: c_associated, c_loc, c_ptr
  implicit none
  real, pointer :: a
  type(c_ptr) :: b
  if(c_associated(b, c_loc(a))) &amp;
     stop 'b and a do not point to same target'
end subroutine association_test
</pre></div>

</dd>
<dt><em>See also</em>:</dt>
<dd><p><a href="C_005fASSOCIATED.html#C_005fASSOCIATED">C_ASSOCIATED</a>, <a href="C_005fFUNLOC.html#C_005fFUNLOC">C_FUNLOC</a>, <a href="C_005fF_005fPOINTER.html#C_005fF_005fPOINTER">C_F_POINTER</a>, <a href="C_005fF_005fPROCPOINTER.html#C_005fF_005fPROCPOINTER">C_F_PROCPOINTER</a>
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