diff options
| author | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
|---|---|---|
| committer | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
| commit | abdaadbcae30fe0c9a66c7516798279fdfd97750 (patch) | |
| tree | 00a54a6e25601e43876d03c1a4a12a749d4a914c /share/doc/gfortran/Argument-list-functions.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
Change-Id: I7303388733328cd98ab9aa3c30236db67f2e9e9c
Diffstat (limited to 'share/doc/gfortran/Argument-list-functions.html')
| -rw-r--r-- | share/doc/gfortran/Argument-list-functions.html | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/share/doc/gfortran/Argument-list-functions.html b/share/doc/gfortran/Argument-list-functions.html new file mode 100644 index 0000000..0d2f1b8 --- /dev/null +++ b/share/doc/gfortran/Argument-list-functions.html @@ -0,0 +1,122 @@ +<!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: Argument list functions</title> + +<meta name="description" content="The GNU Fortran Compiler: Argument list functions"> +<meta name="keywords" content="The GNU Fortran Compiler: Argument list functions"> +<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="Extensions-implemented-in-GNU-Fortran.html#Extensions-implemented-in-GNU-Fortran" rel="up" title="Extensions implemented in GNU Fortran"> +<link href="Read_002fWrite-after-EOF-marker.html#Read_002fWrite-after-EOF-marker" rel="next" title="Read/Write after EOF marker"> +<link href="OpenACC.html#OpenACC" rel="previous" title="OpenACC"> +<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="Argument-list-functions"></a> +<div class="header"> +<p> +Next: <a href="Read_002fWrite-after-EOF-marker.html#Read_002fWrite-after-EOF-marker" accesskey="n" rel="next">Read/Write after EOF marker</a>, Previous: <a href="OpenACC.html#OpenACC" accesskey="p" rel="previous">OpenACC</a>, Up: <a href="Extensions-implemented-in-GNU-Fortran.html#Extensions-implemented-in-GNU-Fortran" accesskey="u" rel="up">Extensions implemented in GNU Fortran</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="Argument-list-functions-_0025VAL_002c-_0025REF-and-_0025LOC"></a> +<h4 class="subsection">5.1.20 Argument list functions <code>%VAL</code>, <code>%REF</code> and <code>%LOC</code></h4> +<a name="index-argument-list-functions"></a> +<a name="index-_0025VAL"></a> +<a name="index-_0025REF"></a> +<a name="index-_0025LOC"></a> + +<p>GNU Fortran supports argument list functions <code>%VAL</code>, <code>%REF</code> +and <code>%LOC</code> statements, for backward compatibility with g77. +It is recommended that these should be used only for code that is +accessing facilities outside of GNU Fortran, such as operating system +or windowing facilities. It is best to constrain such uses to isolated +portions of a program–portions that deal specifically and exclusively +with low-level, system-dependent facilities. Such portions might well +provide a portable interface for use by the program as a whole, but are +themselves not portable, and should be thoroughly tested each time they +are rebuilt using a new compiler or version of a compiler. +</p> +<p><code>%VAL</code> passes a scalar argument by value, <code>%REF</code> passes it by +reference and <code>%LOC</code> passes its memory location. Since gfortran +already passes scalar arguments by reference, <code>%REF</code> is in effect +a do-nothing. <code>%LOC</code> has the same effect as a Fortran pointer. +</p> +<p>An example of passing an argument by value to a C subroutine foo.: +</p><div class="smallexample"> +<pre class="smallexample">C +C prototype void foo_ (float x); +C + external foo + real*4 x + x = 3.14159 + call foo (%VAL (x)) + end +</pre></div> + +<p>For details refer to the g77 manual +<a href="https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/index.html#Top">https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/index.html#Top</a>. +</p> +<p>Also, <code>c_by_val.f</code> and its partner <code>c_by_val.c</code> of the +GNU Fortran testsuite are worth a look. +</p> + + + +</body> +</html> |