| <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> |
| <html> |
| <!-- Copyright (C) 1999-2014 Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with the |
| Invariant Sections being "Funding Free Software", the Front-Cover |
| Texts being (a) (see below), and with the Back-Cover Texts being (b) |
| (see below). A copy of the license is included in the section entitled |
| "GNU Free Documentation License". |
| |
| (a) The FSF's Front-Cover Text is: |
| |
| A GNU Manual |
| |
| (b) The FSF's Back-Cover Text is: |
| |
| You have freedom to copy and modify this GNU Manual, like GNU |
| software. Copies published by the Free Software Foundation raise |
| funds for GNU development. --> |
| <!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ --> |
| <head> |
| <title>The GNU Fortran Compiler: Interoperability with C</title> |
| |
| <meta name="description" content="The GNU Fortran Compiler: Interoperability with C"> |
| <meta name="keywords" content="The GNU Fortran Compiler: Interoperability with C"> |
| <meta name="resource-type" content="document"> |
| <meta name="distribution" content="global"> |
| <meta name="Generator" content="makeinfo"> |
| <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> |
| <link href="index.html#Top" rel="start" title="Top"> |
| <link href="Option-Index.html#Option-Index" rel="index" title="Option Index"> |
| <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> |
| <link href="Mixed_002dLanguage-Programming.html#Mixed_002dLanguage-Programming" rel="up" title="Mixed-Language Programming"> |
| <link href="Intrinsic-Types.html#Intrinsic-Types" rel="next" title="Intrinsic Types"> |
| <link href="Mixed_002dLanguage-Programming.html#Mixed_002dLanguage-Programming" rel="prev" title="Mixed-Language Programming"> |
| <style type="text/css"> |
| <!-- |
| a.summary-letter {text-decoration: none} |
| blockquote.smallquotation {font-size: smaller} |
| div.display {margin-left: 3.2em} |
| div.example {margin-left: 3.2em} |
| div.indentedblock {margin-left: 3.2em} |
| div.lisp {margin-left: 3.2em} |
| div.smalldisplay {margin-left: 3.2em} |
| div.smallexample {margin-left: 3.2em} |
| div.smallindentedblock {margin-left: 3.2em; font-size: smaller} |
| div.smalllisp {margin-left: 3.2em} |
| kbd {font-style:oblique} |
| pre.display {font-family: inherit} |
| pre.format {font-family: inherit} |
| pre.menu-comment {font-family: serif} |
| pre.menu-preformatted {font-family: serif} |
| pre.smalldisplay {font-family: inherit; font-size: smaller} |
| pre.smallexample {font-size: smaller} |
| pre.smallformat {font-family: inherit; font-size: smaller} |
| pre.smalllisp {font-size: smaller} |
| span.nocodebreak {white-space:nowrap} |
| span.nolinebreak {white-space:nowrap} |
| span.roman {font-family:serif; font-weight:normal} |
| span.sansserif {font-family:sans-serif; font-weight:normal} |
| ul.no-bullet {list-style: none} |
| --> |
| </style> |
| |
| |
| </head> |
| |
| <body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> |
| <a name="Interoperability-with-C"></a> |
| <div class="header"> |
| <p> |
| Next: <a href="GNU-Fortran-Compiler-Directives.html#GNU-Fortran-Compiler-Directives" accesskey="n" rel="next">GNU Fortran Compiler Directives</a>, Up: <a href="Mixed_002dLanguage-Programming.html#Mixed_002dLanguage-Programming" accesskey="u" rel="up">Mixed-Language Programming</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p> |
| </div> |
| <hr> |
| <a name="Interoperability-with-C-1"></a> |
| <h3 class="section">7.1 Interoperability with C</h3> |
| |
| <table class="menu" border="0" cellspacing="0"> |
| <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"> |
| </td></tr> |
| <tr><td align="left" valign="top">• <a href="Derived-Types-and-struct.html#Derived-Types-and-struct" accesskey="2">Derived Types and struct</a>:</td><td> </td><td align="left" valign="top"> |
| </td></tr> |
| <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"> |
| </td></tr> |
| <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"> |
| </td></tr> |
| <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"> |
| </td></tr> |
| <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"> |
| </td></tr> |
| </table> |
| |
| <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>). |
| </p> |
| |
| |
| |
| </body> |
| </html> |