You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
474 lines
22 KiB
HTML
474 lines
22 KiB
HTML
4 years ago
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
|
|
<html>
|
||
|
|
<!-- Copyright (C) 1988-2018 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 6.4, http://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<title>Link Options (Using the GNU Compiler Collection (GCC))</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Link Options (Using the GNU Compiler Collection (GCC))">
|
||
|
|
<meta name="keywords" content="Link Options (Using the GNU Compiler Collection (GCC))">
|
||
|
|
<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="Invoking-GCC.html#Invoking-GCC" rel="up" title="Invoking GCC">
|
||
|
|
<link href="Directory-Options.html#Directory-Options" rel="next" title="Directory Options">
|
||
|
|
<link href="Assembler-Options.html#Assembler-Options" rel="prev" title="Assembler Options">
|
||
|
|
<style type="text/css">
|
||
|
|
<!--
|
||
|
|
a.summary-letter {text-decoration: none}
|
||
|
|
blockquote.indentedblock {margin-right: 0em}
|
||
|
|
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
|
||
|
|
blockquote.smallquotation {font-size: smaller}
|
||
|
|
div.display {margin-left: 3.2em}
|
||
|
|
div.example {margin-left: 3.2em}
|
||
|
|
div.lisp {margin-left: 3.2em}
|
||
|
|
div.smalldisplay {margin-left: 3.2em}
|
||
|
|
div.smallexample {margin-left: 3.2em}
|
||
|
|
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.nolinebreak {white-space: nowrap}
|
||
|
|
span.roman {font-family: initial; font-weight: normal}
|
||
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
||
|
|
ul.no-bullet {list-style: none}
|
||
|
|
-->
|
||
|
|
</style>
|
||
|
|
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body lang="en">
|
||
|
|
<a name="Link-Options"></a>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Directory-Options.html#Directory-Options" accesskey="n" rel="next">Directory Options</a>, Previous: <a href="Assembler-Options.html#Assembler-Options" accesskey="p" rel="prev">Assembler Options</a>, Up: <a href="Invoking-GCC.html#Invoking-GCC" accesskey="u" rel="up">Invoking GCC</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="Options-for-Linking"></a>
|
||
|
|
<h3 class="section">3.14 Options for Linking</h3>
|
||
|
|
<a name="index-link-options"></a>
|
||
|
|
<a name="index-options_002c-linking"></a>
|
||
|
|
|
||
|
|
<p>These options come into play when the compiler links object files into
|
||
|
|
an executable output file. They are meaningless if the compiler is
|
||
|
|
not doing a link step.
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dd><a name="index-file-names"></a>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>object-file-name</var></code></dt>
|
||
|
|
<dd><p>A file name that does not end in a special recognized suffix is
|
||
|
|
considered to name an object file or library. (Object files are
|
||
|
|
distinguished from libraries by the linker according to the file
|
||
|
|
contents.) If linking is done, these object files are used as input
|
||
|
|
to the linker.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-c</code></dt>
|
||
|
|
<dt><code>-S</code></dt>
|
||
|
|
<dt><code>-E</code></dt>
|
||
|
|
<dd><a name="index-c-1"></a>
|
||
|
|
<a name="index-S-1"></a>
|
||
|
|
<a name="index-E-1"></a>
|
||
|
|
<p>If any of these options is used, then the linker is not run, and
|
||
|
|
object file names should not be used as arguments. See <a href="Overall-Options.html#Overall-Options">Overall Options</a>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-fuse-ld=bfd</code></dt>
|
||
|
|
<dd><a name="index-fuse_002dld_003dbfd"></a>
|
||
|
|
<p>Use the <code>bfd</code> linker instead of the default linker.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-fuse-ld=gold</code></dt>
|
||
|
|
<dd><a name="index-fuse_002dld_003dgold"></a>
|
||
|
|
<p>Use the <code>gold</code> linker instead of the default linker.
|
||
|
|
</p>
|
||
|
|
<a name="index-Libraries"></a>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-l<var>library</var></code></dt>
|
||
|
|
<dt><code>-l <var>library</var></code></dt>
|
||
|
|
<dd><a name="index-l"></a>
|
||
|
|
<p>Search the library named <var>library</var> when linking. (The second
|
||
|
|
alternative with the library as a separate argument is only for
|
||
|
|
POSIX compliance and is not recommended.)
|
||
|
|
</p>
|
||
|
|
<p>It makes a difference where in the command you write this option; the
|
||
|
|
linker searches and processes libraries and object files in the order they
|
||
|
|
are specified. Thus, ‘<samp>foo.o -lz bar.o</samp>’ searches library ‘<samp>z</samp>’
|
||
|
|
after file <samp>foo.o</samp> but before <samp>bar.o</samp>. If <samp>bar.o</samp> refers
|
||
|
|
to functions in ‘<samp>z</samp>’, those functions may not be loaded.
|
||
|
|
</p>
|
||
|
|
<p>The linker searches a standard list of directories for the library,
|
||
|
|
which is actually a file named <samp>lib<var>library</var>.a</samp>. The linker
|
||
|
|
then uses this file as if it had been specified precisely by name.
|
||
|
|
</p>
|
||
|
|
<p>The directories searched include several standard system directories
|
||
|
|
plus any that you specify with <samp>-L</samp>.
|
||
|
|
</p>
|
||
|
|
<p>Normally the files found this way are library files—archive files
|
||
|
|
whose members are object files. The linker handles an archive file by
|
||
|
|
scanning through it for members which define symbols that have so far
|
||
|
|
been referenced but not defined. But if the file that is found is an
|
||
|
|
ordinary object file, it is linked in the usual fashion. The only
|
||
|
|
difference between using an <samp>-l</samp> option and specifying a file name
|
||
|
|
is that <samp>-l</samp> surrounds <var>library</var> with ‘<samp>lib</samp>’ and ‘<samp>.a</samp>’
|
||
|
|
and searches several directories.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-lobjc</code></dt>
|
||
|
|
<dd><a name="index-lobjc"></a>
|
||
|
|
<p>You need this special case of the <samp>-l</samp> option in order to
|
||
|
|
link an Objective-C or Objective-C++ program.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-nostartfiles</code></dt>
|
||
|
|
<dd><a name="index-nostartfiles"></a>
|
||
|
|
<p>Do not use the standard system startup files when linking.
|
||
|
|
The standard system libraries are used normally, unless <samp>-nostdlib</samp>
|
||
|
|
or <samp>-nodefaultlibs</samp> is used.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-nodefaultlibs</code></dt>
|
||
|
|
<dd><a name="index-nodefaultlibs"></a>
|
||
|
|
<p>Do not use the standard system libraries when linking.
|
||
|
|
Only the libraries you specify are passed to the linker, and options
|
||
|
|
specifying linkage of the system libraries, such as <samp>-static-libgcc</samp>
|
||
|
|
or <samp>-shared-libgcc</samp>, are ignored.
|
||
|
|
The standard startup files are used normally, unless <samp>-nostartfiles</samp>
|
||
|
|
is used.
|
||
|
|
</p>
|
||
|
|
<p>The compiler may generate calls to <code>memcmp</code>,
|
||
|
|
<code>memset</code>, <code>memcpy</code> and <code>memmove</code>.
|
||
|
|
These entries are usually resolved by entries in
|
||
|
|
libc. These entry points should be supplied through some other
|
||
|
|
mechanism when this option is specified.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-nostdlib</code></dt>
|
||
|
|
<dd><a name="index-nostdlib"></a>
|
||
|
|
<p>Do not use the standard system startup files or libraries when linking.
|
||
|
|
No startup files and only the libraries you specify are passed to
|
||
|
|
the linker, and options specifying linkage of the system libraries, such as
|
||
|
|
<samp>-static-libgcc</samp> or <samp>-shared-libgcc</samp>, are ignored.
|
||
|
|
</p>
|
||
|
|
<p>The compiler may generate calls to <code>memcmp</code>, <code>memset</code>,
|
||
|
|
<code>memcpy</code> and <code>memmove</code>.
|
||
|
|
These entries are usually resolved by entries in
|
||
|
|
libc. These entry points should be supplied through some other
|
||
|
|
mechanism when this option is specified.
|
||
|
|
</p>
|
||
|
|
<a name="index-_002dlgcc_002c-use-with-_002dnostdlib"></a>
|
||
|
|
<a name="index-_002dnostdlib-and-unresolved-references"></a>
|
||
|
|
<a name="index-unresolved-references-and-_002dnostdlib"></a>
|
||
|
|
<a name="index-_002dlgcc_002c-use-with-_002dnodefaultlibs"></a>
|
||
|
|
<a name="index-_002dnodefaultlibs-and-unresolved-references"></a>
|
||
|
|
<a name="index-unresolved-references-and-_002dnodefaultlibs"></a>
|
||
|
|
<p>One of the standard libraries bypassed by <samp>-nostdlib</samp> and
|
||
|
|
<samp>-nodefaultlibs</samp> is <samp>libgcc.a</samp>, a library of internal subroutines
|
||
|
|
which GCC uses to overcome shortcomings of particular machines, or special
|
||
|
|
needs for some languages.
|
||
|
|
(See <a href="http://gcc.gnu.org/onlinedocs/gccint/Interface.html#Interface">Interfacing to GCC Output</a> in <cite>GNU Compiler
|
||
|
|
Collection (GCC) Internals</cite>,
|
||
|
|
for more discussion of <samp>libgcc.a</samp>.)
|
||
|
|
In most cases, you need <samp>libgcc.a</samp> even when you want to avoid
|
||
|
|
other standard libraries. In other words, when you specify <samp>-nostdlib</samp>
|
||
|
|
or <samp>-nodefaultlibs</samp> you should usually specify <samp>-lgcc</samp> as well.
|
||
|
|
This ensures that you have no unresolved references to internal GCC
|
||
|
|
library subroutines.
|
||
|
|
(An example of such an internal subroutine is <code>__main</code>, used to ensure C++
|
||
|
|
constructors are called; see <a href="http://gcc.gnu.org/onlinedocs/gccint/Collect2.html#Collect2"><code>collect2</code></a> in <cite>GNU Compiler Collection (GCC) Internals</cite>.)
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-pie</code></dt>
|
||
|
|
<dd><a name="index-pie"></a>
|
||
|
|
<p>Produce a dynamically linked position independent executable on targets
|
||
|
|
that support it. For predictable results, you must also specify the same
|
||
|
|
set of options used for compilation (<samp>-fpie</samp>, <samp>-fPIE</samp>,
|
||
|
|
or model suboptions) when you specify this linker option.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-no-pie</code></dt>
|
||
|
|
<dd><a name="index-no_002dpie"></a>
|
||
|
|
<p>Don’t produce a dynamically linked position independent executable.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-static-pie</code></dt>
|
||
|
|
<dd><a name="index-static_002dpie"></a>
|
||
|
|
<p>Produce a static position independent executable on targets that support
|
||
|
|
it. A static position independent executable is similar to a static
|
||
|
|
executable, but can be loaded at any address without a dynamic linker.
|
||
|
|
For predictable results, you must also specify the same set of options
|
||
|
|
used for compilation (<samp>-fpie</samp>, <samp>-fPIE</samp>, or model
|
||
|
|
suboptions) when you specify this linker option.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-pthread</code></dt>
|
||
|
|
<dd><a name="index-pthread-1"></a>
|
||
|
|
<p>Link with the POSIX threads library. This option is supported on
|
||
|
|
GNU/Linux targets, most other Unix derivatives, and also on
|
||
|
|
x86 Cygwin and MinGW targets. On some targets this option also sets
|
||
|
|
flags for the preprocessor, so it should be used consistently for both
|
||
|
|
compilation and linking.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-rdynamic</code></dt>
|
||
|
|
<dd><a name="index-rdynamic"></a>
|
||
|
|
<p>Pass the flag <samp>-export-dynamic</samp> to the ELF linker, on targets
|
||
|
|
that support it. This instructs the linker to add all symbols, not
|
||
|
|
only used ones, to the dynamic symbol table. This option is needed
|
||
|
|
for some uses of <code>dlopen</code> or to allow obtaining backtraces
|
||
|
|
from within a program.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-s</code></dt>
|
||
|
|
<dd><a name="index-s"></a>
|
||
|
|
<p>Remove all symbol table and relocation information from the executable.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-static</code></dt>
|
||
|
|
<dd><a name="index-static"></a>
|
||
|
|
<p>On systems that support dynamic linking, this overrides <samp>-pie</samp>
|
||
|
|
and prevents linking with the shared libraries. On other systems, this
|
||
|
|
option has no effect.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-shared</code></dt>
|
||
|
|
<dd><a name="index-shared"></a>
|
||
|
|
<p>Produce a shared object which can then be linked with other objects to
|
||
|
|
form an executable. Not all systems support this option. For predictable
|
||
|
|
results, you must also specify the same set of options used for compilation
|
||
|
|
(<samp>-fpic</samp>, <samp>-fPIC</samp>, or model suboptions) when
|
||
|
|
you specify this linker option.<a name="DOCF1" href="#FOOT1"><sup>1</sup></a>
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-shared-libgcc</code></dt>
|
||
|
|
<dt><code>-static-libgcc</code></dt>
|
||
|
|
<dd><a name="index-shared_002dlibgcc"></a>
|
||
|
|
<a name="index-static_002dlibgcc"></a>
|
||
|
|
<p>On systems that provide <samp>libgcc</samp> as a shared library, these options
|
||
|
|
force the use of either the shared or static version, respectively.
|
||
|
|
If no shared version of <samp>libgcc</samp> was built when the compiler was
|
||
|
|
configured, these options have no effect.
|
||
|
|
</p>
|
||
|
|
<p>There are several situations in which an application should use the
|
||
|
|
shared <samp>libgcc</samp> instead of the static version. The most common
|
||
|
|
of these is when the application wishes to throw and catch exceptions
|
||
|
|
across different shared libraries. In that case, each of the libraries
|
||
|
|
as well as the application itself should use the shared <samp>libgcc</samp>.
|
||
|
|
</p>
|
||
|
|
<p>Therefore, the G++ driver automatically adds <samp>-shared-libgcc</samp>
|
||
|
|
whenever you build a shared library or a main executable, because C++
|
||
|
|
programs typically use exceptions, so this is the right thing to do.
|
||
|
|
</p>
|
||
|
|
<p>If, instead, you use the GCC driver to create shared libraries, you may
|
||
|
|
find that they are not always linked with the shared <samp>libgcc</samp>.
|
||
|
|
If GCC finds, at its configuration time, that you have a non-GNU linker
|
||
|
|
or a GNU linker that does not support option <samp>--eh-frame-hdr</samp>,
|
||
|
|
it links the shared version of <samp>libgcc</samp> into shared libraries
|
||
|
|
by default. Otherwise, it takes advantage of the linker and optimizes
|
||
|
|
away the linking with the shared version of <samp>libgcc</samp>, linking with
|
||
|
|
the static version of libgcc by default. This allows exceptions to
|
||
|
|
propagate through such shared libraries, without incurring relocation
|
||
|
|
costs at library load time.
|
||
|
|
</p>
|
||
|
|
<p>However, if a library or main executable is supposed to throw or catch
|
||
|
|
exceptions, you must link it using the G++ driver, or using the option
|
||
|
|
<samp>-shared-libgcc</samp>, such that it is linked with the shared
|
||
|
|
<samp>libgcc</samp>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-static-libasan</code></dt>
|
||
|
|
<dd><a name="index-static_002dlibasan"></a>
|
||
|
|
<p>When the <samp>-fsanitize=address</samp> option is used to link a program,
|
||
|
|
the GCC driver automatically links against <samp>libasan</samp>. If
|
||
|
|
<samp>libasan</samp> is available as a shared library, and the <samp>-static</samp>
|
||
|
|
option is not used, then this links against the shared version of
|
||
|
|
<samp>libasan</samp>. The <samp>-static-libasan</samp> option directs the GCC
|
||
|
|
driver to link <samp>libasan</samp> statically, without necessarily linking
|
||
|
|
other libraries statically.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-static-libtsan</code></dt>
|
||
|
|
<dd><a name="index-static_002dlibtsan"></a>
|
||
|
|
<p>When the <samp>-fsanitize=thread</samp> option is used to link a program,
|
||
|
|
the GCC driver automatically links against <samp>libtsan</samp>. If
|
||
|
|
<samp>libtsan</samp> is available as a shared library, and the <samp>-static</samp>
|
||
|
|
option is not used, then this links against the shared version of
|
||
|
|
<samp>libtsan</samp>. The <samp>-static-libtsan</samp> option directs the GCC
|
||
|
|
driver to link <samp>libtsan</samp> statically, without necessarily linking
|
||
|
|
other libraries statically.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-static-liblsan</code></dt>
|
||
|
|
<dd><a name="index-static_002dliblsan"></a>
|
||
|
|
<p>When the <samp>-fsanitize=leak</samp> option is used to link a program,
|
||
|
|
the GCC driver automatically links against <samp>liblsan</samp>. If
|
||
|
|
<samp>liblsan</samp> is available as a shared library, and the <samp>-static</samp>
|
||
|
|
option is not used, then this links against the shared version of
|
||
|
|
<samp>liblsan</samp>. The <samp>-static-liblsan</samp> option directs the GCC
|
||
|
|
driver to link <samp>liblsan</samp> statically, without necessarily linking
|
||
|
|
other libraries statically.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-static-libubsan</code></dt>
|
||
|
|
<dd><a name="index-static_002dlibubsan"></a>
|
||
|
|
<p>When the <samp>-fsanitize=undefined</samp> option is used to link a program,
|
||
|
|
the GCC driver automatically links against <samp>libubsan</samp>. If
|
||
|
|
<samp>libubsan</samp> is available as a shared library, and the <samp>-static</samp>
|
||
|
|
option is not used, then this links against the shared version of
|
||
|
|
<samp>libubsan</samp>. The <samp>-static-libubsan</samp> option directs the GCC
|
||
|
|
driver to link <samp>libubsan</samp> statically, without necessarily linking
|
||
|
|
other libraries statically.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-static-libmpx</code></dt>
|
||
|
|
<dd><a name="index-static_002dlibmpx"></a>
|
||
|
|
<p>When the <samp>-fcheck-pointer bounds</samp> and <samp>-mmpx</samp> options are
|
||
|
|
used to link a program, the GCC driver automatically links against
|
||
|
|
<samp>libmpx</samp>. If <samp>libmpx</samp> is available as a shared library,
|
||
|
|
and the <samp>-static</samp> option is not used, then this links against
|
||
|
|
the shared version of <samp>libmpx</samp>. The <samp>-static-libmpx</samp>
|
||
|
|
option directs the GCC driver to link <samp>libmpx</samp> statically,
|
||
|
|
without necessarily linking other libraries statically.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-static-libmpxwrappers</code></dt>
|
||
|
|
<dd><a name="index-static_002dlibmpxwrappers"></a>
|
||
|
|
<p>When the <samp>-fcheck-pointer bounds</samp> and <samp>-mmpx</samp> options are used
|
||
|
|
to link a program without also using <samp>-fno-chkp-use-wrappers</samp>, the
|
||
|
|
GCC driver automatically links against <samp>libmpxwrappers</samp>. If
|
||
|
|
<samp>libmpxwrappers</samp> is available as a shared library, and the
|
||
|
|
<samp>-static</samp> option is not used, then this links against the shared
|
||
|
|
version of <samp>libmpxwrappers</samp>. The <samp>-static-libmpxwrappers</samp>
|
||
|
|
option directs the GCC driver to link <samp>libmpxwrappers</samp> statically,
|
||
|
|
without necessarily linking other libraries statically.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-static-libstdc++</code></dt>
|
||
|
|
<dd><a name="index-static_002dlibstdc_002b_002b"></a>
|
||
|
|
<p>When the <code>g++</code> program is used to link a C++ program, it
|
||
|
|
normally automatically links against <samp>libstdc++</samp>. If
|
||
|
|
<samp>libstdc++</samp> is available as a shared library, and the
|
||
|
|
<samp>-static</samp> option is not used, then this links against the
|
||
|
|
shared version of <samp>libstdc++</samp>. That is normally fine. However, it
|
||
|
|
is sometimes useful to freeze the version of <samp>libstdc++</samp> used by
|
||
|
|
the program without going all the way to a fully static link. The
|
||
|
|
<samp>-static-libstdc++</samp> option directs the <code>g++</code> driver to
|
||
|
|
link <samp>libstdc++</samp> statically, without necessarily linking other
|
||
|
|
libraries statically.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-symbolic</code></dt>
|
||
|
|
<dd><a name="index-symbolic"></a>
|
||
|
|
<p>Bind references to global symbols when building a shared object. Warn
|
||
|
|
about any unresolved references (unless overridden by the link editor
|
||
|
|
option <samp>-Xlinker -z -Xlinker defs</samp>). Only a few systems support
|
||
|
|
this option.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-T <var>script</var></code></dt>
|
||
|
|
<dd><a name="index-T"></a>
|
||
|
|
<a name="index-linker-script"></a>
|
||
|
|
<p>Use <var>script</var> as the linker script. This option is supported by most
|
||
|
|
systems using the GNU linker. On some targets, such as bare-board
|
||
|
|
targets without an operating system, the <samp>-T</samp> option may be required
|
||
|
|
when linking to avoid references to undefined symbols.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-Xlinker <var>option</var></code></dt>
|
||
|
|
<dd><a name="index-Xlinker"></a>
|
||
|
|
<p>Pass <var>option</var> as an option to the linker. You can use this to
|
||
|
|
supply system-specific linker options that GCC does not recognize.
|
||
|
|
</p>
|
||
|
|
<p>If you want to pass an option that takes a separate argument, you must use
|
||
|
|
<samp>-Xlinker</samp> twice, once for the option and once for the argument.
|
||
|
|
For example, to pass <samp>-assert definitions</samp>, you must write
|
||
|
|
<samp>-Xlinker -assert -Xlinker definitions</samp>. It does not work to write
|
||
|
|
<samp>-Xlinker "-assert definitions"</samp>, because this passes the entire
|
||
|
|
string as a single argument, which is not what the linker expects.
|
||
|
|
</p>
|
||
|
|
<p>When using the GNU linker, it is usually more convenient to pass
|
||
|
|
arguments to linker options using the <samp><var>option</var>=<var>value</var></samp>
|
||
|
|
syntax than as separate arguments. For example, you can specify
|
||
|
|
<samp>-Xlinker -Map=output.map</samp> rather than
|
||
|
|
<samp>-Xlinker -Map -Xlinker output.map</samp>. Other linkers may not support
|
||
|
|
this syntax for command-line options.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-Wl,<var>option</var></code></dt>
|
||
|
|
<dd><a name="index-Wl"></a>
|
||
|
|
<p>Pass <var>option</var> as an option to the linker. If <var>option</var> contains
|
||
|
|
commas, it is split into multiple options at the commas. You can use this
|
||
|
|
syntax to pass an argument to the option.
|
||
|
|
For example, <samp>-Wl,-Map,output.map</samp> passes <samp>-Map output.map</samp> to the
|
||
|
|
linker. When using the GNU linker, you can also get the same effect with
|
||
|
|
<samp>-Wl,-Map=output.map</samp>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-u <var>symbol</var></code></dt>
|
||
|
|
<dd><a name="index-u"></a>
|
||
|
|
<p>Pretend the symbol <var>symbol</var> is undefined, to force linking of
|
||
|
|
library modules to define it. You can use <samp>-u</samp> multiple times with
|
||
|
|
different symbols to force loading of additional library modules.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-z <var>keyword</var></code></dt>
|
||
|
|
<dd><a name="index-z"></a>
|
||
|
|
<p><samp>-z</samp> is passed directly on to the linker along with the keyword
|
||
|
|
<var>keyword</var>. See the section in the documentation of your linker for
|
||
|
|
permitted values and their meanings.
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<div class="footnote">
|
||
|
|
<hr>
|
||
|
|
<h4 class="footnotes-heading">Footnotes</h4>
|
||
|
|
|
||
|
|
<h3><a name="FOOT1" href="#DOCF1">(1)</a></h3>
|
||
|
|
<p>On some systems, ‘<samp>gcc -shared</samp>’
|
||
|
|
needs to build supplementary stub code for constructors to work. On
|
||
|
|
multi-libbed systems, ‘<samp>gcc -shared</samp>’ must select the correct support
|
||
|
|
libraries to link against. Failing to supply the correct flags may lead
|
||
|
|
to subtle defects. Supplying them in cases where they are not necessary
|
||
|
|
is innocuous.</p>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Directory-Options.html#Directory-Options" accesskey="n" rel="next">Directory Options</a>, Previous: <a href="Assembler-Options.html#Assembler-Options" accesskey="p" rel="prev">Assembler Options</a>, Up: <a href="Invoking-GCC.html#Invoking-GCC" accesskey="u" rel="up">Invoking GCC</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>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|