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| author | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
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| committer | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
| commit | abdaadbcae30fe0c9a66c7516798279fdfd97750 (patch) | |
| tree | 00a54a6e25601e43876d03c1a4a12a749d4a914c /share/doc/gfortran/Interoperable-Global-Variables.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
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diff --git a/share/doc/gfortran/Interoperable-Global-Variables.html b/share/doc/gfortran/Interoperable-Global-Variables.html new file mode 100644 index 0000000..162b4ee --- /dev/null +++ b/share/doc/gfortran/Interoperable-Global-Variables.html @@ -0,0 +1,111 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1999-2023 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 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>The GNU Fortran Compiler: Interoperable Global Variables</title> + +<meta name="description" content="The GNU Fortran Compiler: Interoperable Global Variables"> +<meta name="keywords" content="The GNU Fortran Compiler: Interoperable Global Variables"> +<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="Interoperability-with-C.html#Interoperability-with-C" rel="up" title="Interoperability with C"> +<link href="Interoperable-Subroutines-and-Functions.html#Interoperable-Subroutines-and-Functions" rel="next" title="Interoperable Subroutines and Functions"> +<link href="Derived-Types-and-struct.html#Derived-Types-and-struct" rel="previous" title="Derived Types and struct"> +<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="Interoperable-Global-Variables"></a> +<div class="header"> +<p> +Next: <a href="Interoperable-Subroutines-and-Functions.html#Interoperable-Subroutines-and-Functions" accesskey="n" rel="next">Interoperable Subroutines and Functions</a>, Previous: <a href="Derived-Types-and-struct.html#Derived-Types-and-struct" accesskey="p" rel="previous">Derived Types and struct</a>, Up: <a href="Interoperability-with-C.html#Interoperability-with-C" accesskey="u" rel="up">Interoperability with C</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="Interoperable-Global-Variables-1"></a> +<h4 class="subsection">6.1.3 Interoperable Global Variables</h4> +<a name="index-C-variable-interoperability"></a> +<a name="index-variable-interoperability-with-C"></a> +<a name="index-interoperability_002c-variable"></a> + +<p>Variables can be made accessible from C using the C binding attribute, +optionally together with specifying a binding name. Those variables +have to be declared in the declaration part of a <code>MODULE</code>, +be of interoperable type, and have neither the <code>pointer</code> nor +the <code>allocatable</code> attribute. +</p> +<div class="smallexample"> +<pre class="smallexample"> MODULE m + USE myType_module + USE ISO_C_BINDING + integer(C_INT), bind(C, name="_MyProject_flags") :: global_flag + type(myType), bind(C) :: tp + END MODULE +</pre></div> + +<p>Here, <code>_MyProject_flags</code> is the case-sensitive name of the variable +as seen from C programs while <code>global_flag</code> is the case-insensitive +name as seen from Fortran. If no binding name is specified, as for +<var>tp</var>, the C binding name is the (lowercase) Fortran binding name. +If a binding name is specified, only a single variable may be after the +double colon. Note of warning: You cannot use a global variable to +access <var>errno</var> of the C library as the C standard allows it to be +a macro. Use the <code>IERRNO</code> intrinsic (GNU extension) instead. +</p> + + + +</body> +</html> |