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| <h3 class="section">7.1 Interoperability with C</h3> |
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| <tr><td align="left" valign="top">• <a href="Intrinsic-Types.html#Intrinsic-Types" accesskey="1">Intrinsic Types</a>:</td><td> </td><td align="left" valign="top"> |
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| <tr><td align="left" valign="top">• <a href="Interoperable-Global-Variables.html#Interoperable-Global-Variables" accesskey="3">Interoperable Global Variables</a>:</td><td> </td><td align="left" valign="top"> |
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| <tr><td align="left" valign="top">• <a href="Interoperable-Subroutines-and-Functions.html#Interoperable-Subroutines-and-Functions" accesskey="4">Interoperable Subroutines and Functions</a>:</td><td> </td><td align="left" valign="top"> |
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| <tr><td align="left" valign="top">• <a href="Working-with-Pointers.html#Working-with-Pointers" accesskey="5">Working with Pointers</a>:</td><td> </td><td align="left" valign="top"> |
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| <tr><td align="left" valign="top">• <a href="Further-Interoperability-of-Fortran-with-C.html#Further-Interoperability-of-Fortran-with-C" accesskey="6">Further Interoperability of Fortran with C</a>:</td><td> </td><td align="left" valign="top"> |
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| <p>Since Fortran 2003 (ISO/IEC 1539-1:2004(E)) there is a |
| standardized way to generate procedure and derived-type |
| declarations and global variables which are interoperable with C |
| (ISO/IEC 9899:1999). The <code>bind(C)</code> attribute has been added |
| to inform the compiler that a symbol shall be interoperable with C; |
| also, some constraints are added. Note, however, that not |
| all C features have a Fortran equivalent or vice versa. For instance, |
| neither C’s unsigned integers nor C’s functions with variable number |
| of arguments have an equivalent in Fortran. |
| </p> |
| <p>Note that array dimensions are reversely ordered in C and that arrays in |
| C always start with index 0 while in Fortran they start by default with |
| 1. Thus, an array declaration <code>A(n,m)</code> in Fortran matches |
| <code>A[m][n]</code> in C and accessing the element <code>A(i,j)</code> matches |
| <code>A[j-1][i-1]</code>. The element following <code>A(i,j)</code> (C: <code>A[j-1][i-1]</code>; |
| assuming <em>i < n</em>) in memory is <code>A(i+1,j)</code> (C: <code>A[j-1][i]</code>). |
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