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diff --git a/share/doc/gcc/Microsoft-Windows-Function-Attributes.html b/share/doc/gcc/Microsoft-Windows-Function-Attributes.html new file mode 100644 index 0000000..8467f4f --- /dev/null +++ b/share/doc/gcc/Microsoft-Windows-Function-Attributes.html @@ -0,0 +1,189 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- This file documents the use of the GNU compilers. + +Copyright (C) 1988-2023 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). 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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>Using the GNU Compiler Collection (GCC): Microsoft Windows Function Attributes</title> + +<meta name="description" content="Using the GNU Compiler Collection (GCC): Microsoft Windows Function Attributes"> +<meta name="keywords" content="Using the GNU Compiler Collection (GCC): Microsoft Windows Function Attributes"> +<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="Indices.html#Indices" rel="index" title="Indices"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Function-Attributes.html#Function-Attributes" rel="up" title="Function Attributes"> +<link href="MIPS-Function-Attributes.html#MIPS-Function-Attributes" rel="next" title="MIPS Function Attributes"> +<link href="MicroBlaze-Function-Attributes.html#MicroBlaze-Function-Attributes" rel="previous" title="MicroBlaze Function Attributes"> +<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_US" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Microsoft-Windows-Function-Attributes"></a> +<div class="header"> +<p> +Next: <a href="MIPS-Function-Attributes.html#MIPS-Function-Attributes" accesskey="n" rel="next">MIPS Function Attributes</a>, Previous: <a href="MicroBlaze-Function-Attributes.html#MicroBlaze-Function-Attributes" accesskey="p" rel="previous">MicroBlaze Function Attributes</a>, Up: <a href="Function-Attributes.html#Function-Attributes" accesskey="u" rel="up">Function Attributes</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Indices.html#Indices" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="Microsoft-Windows-Function-Attributes-1"></a> +<h4 class="subsection">6.33.18 Microsoft Windows Function Attributes</h4> + +<p>The following attributes are available on Microsoft Windows and Symbian OS +targets. +</p> +<dl compact="compact"> +<dd><a name="index-dllexport-function-attribute"></a> +<a name="index-_005f_005fdeclspec_0028dllexport_0029"></a> +</dd> +<dt><code>dllexport</code></dt> +<dd><p>On Microsoft Windows targets and Symbian OS targets the +<code>dllexport</code> attribute causes the compiler to provide a global +pointer to a pointer in a DLL, so that it can be referenced with the +<code>dllimport</code> attribute. On Microsoft Windows targets, the pointer +name is formed by combining <code>_imp__</code> and the function or variable +name. +</p> +<p>You can use <code>__declspec(dllexport)</code> as a synonym for +<code>__attribute__ ((dllexport))</code> for compatibility with other +compilers. +</p> +<p>On systems that support the <code>visibility</code> attribute, this +attribute also implies “default” visibility. It is an error to +explicitly specify any other visibility. +</p> +<p>GCC’s default behavior is to emit all inline functions with the +<code>dllexport</code> attribute. Since this can cause object file-size bloat, +you can use <samp>-fno-keep-inline-dllexport</samp>, which tells GCC to +ignore the attribute for inlined functions unless the +<samp>-fkeep-inline-functions</samp> flag is used instead. +</p> +<p>The attribute is ignored for undefined symbols. +</p> +<p>When applied to C++ classes, the attribute marks defined non-inlined +member functions and static data members as exports. Static consts +initialized in-class are not marked unless they are also defined +out-of-class. +</p> +<p>For Microsoft Windows targets there are alternative methods for +including the symbol in the DLL’s export table such as using a +<samp>.def</samp> file with an <code>EXPORTS</code> section or, with GNU ld, using +the <samp>--export-all</samp> linker flag. +</p> +<a name="index-dllimport-function-attribute"></a> +<a name="index-_005f_005fdeclspec_0028dllimport_0029"></a> +</dd> +<dt><code>dllimport</code></dt> +<dd><p>On Microsoft Windows and Symbian OS targets, the <code>dllimport</code> +attribute causes the compiler to reference a function or variable via +a global pointer to a pointer that is set up by the DLL exporting the +symbol. The attribute implies <code>extern</code>. On Microsoft Windows +targets, the pointer name is formed by combining <code>_imp__</code> and the +function or variable name. +</p> +<p>You can use <code>__declspec(dllimport)</code> as a synonym for +<code>__attribute__ ((dllimport))</code> for compatibility with other +compilers. +</p> +<p>On systems that support the <code>visibility</code> attribute, this +attribute also implies “default” visibility. It is an error to +explicitly specify any other visibility. +</p> +<p>Currently, the attribute is ignored for inlined functions. If the +attribute is applied to a symbol <em>definition</em>, an error is reported. +If a symbol previously declared <code>dllimport</code> is later defined, the +attribute is ignored in subsequent references, and a warning is emitted. +The attribute is also overridden by a subsequent declaration as +<code>dllexport</code>. +</p> +<p>When applied to C++ classes, the attribute marks non-inlined +member functions and static data members as imports. However, the +attribute is ignored for virtual methods to allow creation of vtables +using thunks. +</p> +<p>On the SH Symbian OS target the <code>dllimport</code> attribute also has +another affect—it can cause the vtable and run-time type information +for a class to be exported. This happens when the class has a +dllimported constructor or a non-inline, non-pure virtual function +and, for either of those two conditions, the class also has an inline +constructor or destructor and has a key function that is defined in +the current translation unit. +</p> +<p>For Microsoft Windows targets the use of the <code>dllimport</code> +attribute on functions is not necessary, but provides a small +performance benefit by eliminating a thunk in the DLL. The use of the +<code>dllimport</code> attribute on imported variables can be avoided by passing the +<samp>--enable-auto-import</samp> switch to the GNU linker. As with +functions, using the attribute for a variable eliminates a thunk in +the DLL. +</p> +<p>One drawback to using this attribute is that a pointer to a +<em>variable</em> marked as <code>dllimport</code> cannot be used as a constant +address. However, a pointer to a <em>function</em> with the +<code>dllimport</code> attribute can be used as a constant initializer; in +this case, the address of a stub function in the import lib is +referenced. On Microsoft Windows targets, the attribute can be disabled +for functions by setting the <samp>-mnop-fun-dllimport</samp> flag. +</p></dd> +</dl> + +<hr> +<div class="header"> +<p> +Next: <a href="MIPS-Function-Attributes.html#MIPS-Function-Attributes" accesskey="n" rel="next">MIPS Function Attributes</a>, Previous: <a href="MicroBlaze-Function-Attributes.html#MicroBlaze-Function-Attributes" accesskey="p" rel="previous">MicroBlaze Function Attributes</a>, Up: <a href="Function-Attributes.html#Function-Attributes" accesskey="u" rel="up">Function Attributes</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Indices.html#Indices" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |