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| <h4 class="subsection">7.1.2 Derived Types and struct</h4> |
| |
| <p>For compatibility of derived types with <code>struct</code>, one needs to use |
| the <code>BIND(C)</code> attribute in the type declaration. For instance, the |
| following type declaration |
| </p> |
| <div class="smallexample"> |
| <pre class="smallexample"> USE ISO_C_BINDING |
| TYPE, BIND(C) :: myType |
| INTEGER(C_INT) :: i1, i2 |
| INTEGER(C_SIGNED_CHAR) :: i3 |
| REAL(C_DOUBLE) :: d1 |
| COMPLEX(C_FLOAT_COMPLEX) :: c1 |
| CHARACTER(KIND=C_CHAR) :: str(5) |
| END TYPE |
| </pre></div> |
| |
| <p>matches the following <code>struct</code> declaration in C |
| </p> |
| <div class="smallexample"> |
| <pre class="smallexample"> struct { |
| int i1, i2; |
| /* Note: "char" might be signed or unsigned. */ |
| signed char i3; |
| double d1; |
| float _Complex c1; |
| char str[5]; |
| } myType; |
| </pre></div> |
| |
| <p>Derived types with the C binding attribute shall not have the <code>sequence</code> |
| attribute, type parameters, the <code>extends</code> attribute, nor type-bound |
| procedures. Every component must be of interoperable type and kind and may not |
| have the <code>pointer</code> or <code>allocatable</code> attribute. The names of the |
| components are irrelevant for interoperability. |
| </p> |
| <p>As there exist no direct Fortran equivalents, neither unions nor structs |
| with bit field or variable-length array members are interoperable. |
| </p> |
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