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<h3 class="section">9.2 <code>ISO_C_BINDING</code></h3>
<dl>
<dt><em>Standard</em>:<dd>Fortran 2003 and later, GNU extensions
</dl>
<p>The following intrinsic procedures are provided by the module; their
definition can be found in the section Intrinsic Procedures of this
manual.
<dl>
<dt><code>C_ASSOCIATED</code><br><dt><code>C_F_POINTER</code><br><dt><code>C_F_PROCPOINTER</code><br><dt><code>C_FUNLOC</code><br><dt><code>C_LOC</code><br><dt><code>C_SIZEOF</code><dd></dl>
<!-- TODO: Vertical spacing between C_FUNLOC and C_LOC wrong in PDF, -->
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<p>The <code>ISO_C_BINDING</code> module provides the following named constants of
type default integer, which can be used as KIND type parameters.
<p>In addition to the integer named constants required by the Fortran 2003
standard, GNU Fortran provides as an extension named constants for the
128-bit integer types supported by the C compiler: <code>C_INT128_T,
C_INT_LEAST128_T, C_INT_FAST128_T</code>.
<p><table summary=""><tr align="left"><td valign="top" width="15%">Fortran Type </td><td valign="top" width="35%">Named constant </td><td valign="top" width="35%">C type </td><td valign="top" width="35%">Extension
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT</code> </td><td valign="top" width="35%"><code>int</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_SHORT</code> </td><td valign="top" width="35%"><code>short int</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_LONG</code> </td><td valign="top" width="35%"><code>long int</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_LONG_LONG</code> </td><td valign="top" width="35%"><code>long long int</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_SIGNED_CHAR</code> </td><td valign="top" width="35%"><code>signed char</code>/<code>unsigned char</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_SIZE_T</code> </td><td valign="top" width="35%"><code>size_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT8_T</code> </td><td valign="top" width="35%"><code>int8_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT16_T</code> </td><td valign="top" width="35%"><code>int16_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT32_T</code> </td><td valign="top" width="35%"><code>int32_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT64_T</code> </td><td valign="top" width="35%"><code>int64_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT128_T</code> </td><td valign="top" width="35%"><code>int128_t</code> </td><td valign="top" width="35%">Ext.
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT_LEAST8_T</code> </td><td valign="top" width="35%"><code>int_least8_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT_LEAST16_T</code> </td><td valign="top" width="35%"><code>int_least16_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT_LEAST32_T</code> </td><td valign="top" width="35%"><code>int_least32_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT_LEAST64_T</code> </td><td valign="top" width="35%"><code>int_least64_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT_LEAST128_T</code></td><td valign="top" width="35%"><code>int_least128_t</code> </td><td valign="top" width="35%">Ext.
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT_FAST8_T</code> </td><td valign="top" width="35%"><code>int_fast8_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT_FAST16_T</code> </td><td valign="top" width="35%"><code>int_fast16_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT_FAST32_T</code> </td><td valign="top" width="35%"><code>int_fast32_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT_FAST64_T</code> </td><td valign="top" width="35%"><code>int_fast64_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INT_FAST128_T</code> </td><td valign="top" width="35%"><code>int_fast128_t</code> </td><td valign="top" width="35%">Ext.
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INTMAX_T</code> </td><td valign="top" width="35%"><code>intmax_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>INTEGER</code></td><td valign="top" width="35%"><code>C_INTPTR_T</code> </td><td valign="top" width="35%"><code>intptr_t</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>REAL</code> </td><td valign="top" width="35%"><code>C_FLOAT</code> </td><td valign="top" width="35%"><code>float</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>REAL</code> </td><td valign="top" width="35%"><code>C_DOUBLE</code> </td><td valign="top" width="35%"><code>double</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>REAL</code> </td><td valign="top" width="35%"><code>C_LONG_DOUBLE</code> </td><td valign="top" width="35%"><code>long double</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>COMPLEX</code></td><td valign="top" width="35%"><code>C_FLOAT_COMPLEX</code> </td><td valign="top" width="35%"><code>float _Complex</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>COMPLEX</code></td><td valign="top" width="35%"><code>C_DOUBLE_COMPLEX</code></td><td valign="top" width="35%"><code>double _Complex</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>COMPLEX</code></td><td valign="top" width="35%"><code>C_LONG_DOUBLE_COMPLEX</code></td><td valign="top" width="35%"><code>long double _Complex</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>LOGICAL</code></td><td valign="top" width="35%"><code>C_BOOL</code> </td><td valign="top" width="35%"><code>_Bool</code>
<br></td></tr><tr align="left"><td valign="top" width="15%"><code>CHARACTER</code></td><td valign="top" width="35%"><code>C_CHAR</code> </td><td valign="top" width="35%"><code>char</code>
<br></td></tr></table>
<p>Additionally, the following parameters of type <code>CHARACTER(KIND=C_CHAR)</code>
are defined.
<p><table summary=""><tr align="left"><td valign="top" width="20%">Name </td><td valign="top" width="45%">C definition </td><td valign="top" width="15%">Value
<br></td></tr><tr align="left"><td valign="top" width="20%"><code>C_NULL_CHAR</code> </td><td valign="top" width="45%">null character </td><td valign="top" width="15%"><code>'\0'</code>
<br></td></tr><tr align="left"><td valign="top" width="20%"><code>C_ALERT</code> </td><td valign="top" width="45%">alert </td><td valign="top" width="15%"><code>'\a'</code>
<br></td></tr><tr align="left"><td valign="top" width="20%"><code>C_BACKSPACE</code> </td><td valign="top" width="45%">backspace </td><td valign="top" width="15%"><code>'\b'</code>
<br></td></tr><tr align="left"><td valign="top" width="20%"><code>C_FORM_FEED</code> </td><td valign="top" width="45%">form feed </td><td valign="top" width="15%"><code>'\f'</code>
<br></td></tr><tr align="left"><td valign="top" width="20%"><code>C_NEW_LINE</code> </td><td valign="top" width="45%">new line </td><td valign="top" width="15%"><code>'\n'</code>
<br></td></tr><tr align="left"><td valign="top" width="20%"><code>C_CARRIAGE_RETURN</code> </td><td valign="top" width="45%">carriage return </td><td valign="top" width="15%"><code>'\r'</code>
<br></td></tr><tr align="left"><td valign="top" width="20%"><code>C_HORIZONTAL_TAB</code> </td><td valign="top" width="45%">horizontal tab </td><td valign="top" width="15%"><code>'\t'</code>
<br></td></tr><tr align="left"><td valign="top" width="20%"><code>C_VERTICAL_TAB</code> </td><td valign="top" width="45%">vertical tab </td><td valign="top" width="15%"><code>'\v'</code>
<br></td></tr></table>
<p>Moreover, the following two named constants are defined:
<p><table summary=""><tr align="left"><td valign="top" width="20%">Name </td><td valign="top" width="80%">Type
<br></td></tr><tr align="left"><td valign="top" width="20%"><code>C_NULL_PTR</code> </td><td valign="top" width="80%"><code>C_PTR</code>
<br></td></tr><tr align="left"><td valign="top" width="20%"><code>C_NULL_FUNPTR</code> </td><td valign="top" width="80%"><code>C_FUNPTR</code>
<br></td></tr></table>
<p>Both are equivalent to the value <code>NULL</code> in C.
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