284 lines
14 KiB
XML
284 lines
14 KiB
XML
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<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
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[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
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<chapter id='sdk-working-projects'>
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<title>Using the SDK Toolchain Directly</title>
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<para>
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You can use the SDK toolchain directly with Makefile,
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Autotools, and <trademark class='trade'>Eclipse</trademark> based
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projects.
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This chapter covers the first two, while the
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"<link linkend='sdk-eclipse-project'>Developing Applications Using <trademark class='trade'>Eclipse</trademark></link>"
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Chapter covers the latter.
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</para>
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<section id='autotools-based-projects'>
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<title>Autotools-Based Projects</title>
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<para>
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Once you have a suitable cross-toolchain installed, it is very easy
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to develop a project outside of the OpenEmbedded build system.
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This section presents a simple "Helloworld" example that shows how
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to set up, compile, and run the project.
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</para>
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<section id='creating-and-running-a-project-based-on-gnu-autotools'>
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<title>Creating and Running a Project Based on GNU Autotools</title>
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<para>
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Follow these steps to create a simple Autotools-based project:
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<orderedlist>
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<listitem><para>
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<emphasis>Create your directory:</emphasis>
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Create a clean directory for your project and then make
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that directory your working location:
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<literallayout class='monospaced'>
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$ mkdir $HOME/helloworld
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$ cd $HOME/helloworld
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</literallayout>
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</para></listitem>
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<listitem><para>
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<emphasis>Populate the directory:</emphasis>
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Create <filename>hello.c</filename>,
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<filename>Makefile.am</filename>,
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and <filename>configure.ac</filename> files as follows:
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<itemizedlist>
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<listitem><para>
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For <filename>hello.c</filename>, include
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these lines:
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<literallayout class='monospaced'>
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#include <stdio.h>
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main()
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{
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printf("Hello World!\n");
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}
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</literallayout>
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</para></listitem>
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<listitem><para>
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For <filename>Makefile.am</filename>,
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include these lines:
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<literallayout class='monospaced'>
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bin_PROGRAMS = hello
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hello_SOURCES = hello.c
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</literallayout>
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</para></listitem>
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<listitem><para>
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For <filename>configure.in</filename>,
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include these lines:
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<literallayout class='monospaced'>
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AC_INIT(hello,0.1)
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AM_INIT_AUTOMAKE([foreign])
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AC_PROG_CC
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AC_PROG_INSTALL
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AC_OUTPUT(Makefile)
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</literallayout>
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</para></listitem>
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</itemizedlist>
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</para></listitem>
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<listitem><para>
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<emphasis>Source the cross-toolchain
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environment setup file:</emphasis>
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As described earlier in the manual, installing the
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cross-toolchain creates a cross-toolchain
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environment setup script in the directory that the SDK
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was installed.
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Before you can use the tools to develop your project,
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you must source this setup script.
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The script begins with the string "environment-setup"
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and contains the machine architecture, which is
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followed by the string "poky-linux".
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Here is an example that sources a script from the
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default SDK installation directory that uses the
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32-bit Intel x86 Architecture and the
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&DISTRO_NAME; Yocto Project release:
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<literallayout class='monospaced'>
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$ source /opt/poky/&DISTRO;/environment-setup-i586-poky-linux
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</literallayout>
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</para></listitem>
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<listitem><para>
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<emphasis>Generate the local aclocal.m4
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files and create the configure script:</emphasis>
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The following GNU Autotools generate the local
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<filename>aclocal.m4</filename> files and create the
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configure script:
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<literallayout class='monospaced'>
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$ aclocal
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$ autoconf
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</literallayout>
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</para></listitem>
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<listitem><para>
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<emphasis>Generate files needed by GNU coding
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standards:</emphasis>
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GNU coding standards require certain files in order
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for the project to be compliant.
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This command creates those files:
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<literallayout class='monospaced'>
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$ touch NEWS README AUTHORS ChangeLog
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</literallayout>
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</para></listitem>
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<listitem><para>
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<emphasis>Generate the configure file:</emphasis>
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This command generates the
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<filename>configure</filename>:
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<literallayout class='monospaced'>
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$ automake -a
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</literallayout>
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</para></listitem>
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<listitem><para>
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<emphasis>Cross-compile the project:</emphasis>
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This command compiles the project using the
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cross-compiler.
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The
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<ulink url='&YOCTO_DOCS_REF_URL;#var-CONFIGURE_FLAGS'><filename>CONFIGURE_FLAGS</filename></ulink>
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environment variable provides the minimal arguments for
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GNU configure:
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<literallayout class='monospaced'>
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$ ./configure ${CONFIGURE_FLAGS}
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</literallayout>
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</para></listitem>
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<listitem><para>
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<emphasis>Make and install the project:</emphasis>
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These two commands generate and install the project
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into the destination directory:
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<literallayout class='monospaced'>
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$ make
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$ make install DESTDIR=./tmp
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</literallayout>
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</para></listitem>
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<listitem><para>
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<emphasis>Verify the installation:</emphasis>
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This command is a simple way to verify the installation
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of your project.
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Running the command prints the architecture on which
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the binary file can run.
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This architecture should be the same architecture that
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the installed cross-toolchain supports.
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<literallayout class='monospaced'>
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$ file ./tmp/usr/local/bin/hello
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</literallayout>
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</para></listitem>
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<listitem><para>
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<emphasis>Execute your project:</emphasis>
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To execute the project in the shell, simply enter
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the name.
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You could also copy the binary to the actual target
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hardware and run the project there as well:
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<literallayout class='monospaced'>
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$ ./hello
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</literallayout>
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As expected, the project displays the "Hello World!"
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message.
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</para></listitem>
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</orderedlist>
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</para>
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</section>
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<section id='passing-host-options'>
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<title>Passing Host Options</title>
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<para>
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For an Autotools-based project, you can use the cross-toolchain
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by just passing the appropriate host option to
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<filename>configure.sh</filename>.
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The host option you use is derived from the name of the
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environment setup script found in the directory in which you
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installed the cross-toolchain.
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For example, the host option for an ARM-based target that uses
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the GNU EABI is <filename>armv5te-poky-linux-gnueabi</filename>.
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You will notice that the name of the script is
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<filename>environment-setup-armv5te-poky-linux-gnueabi</filename>.
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Thus, the following command works to update your project and
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rebuild it using the appropriate cross-toolchain tools:
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<literallayout class='monospaced'>
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$ ./configure --host=armv5te-poky-linux-gnueabi \
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--with-libtool-sysroot=<replaceable>sysroot_dir</replaceable>
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</literallayout>
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<note>
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If the <filename>configure</filename> script results in
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problems recognizing the
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<filename>--with-libtool-sysroot=</filename><replaceable>sysroot-dir</replaceable>
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option, regenerate the script to enable the support by
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doing the following and then run the script again:
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<literallayout class='monospaced'>
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$ libtoolize --automake
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$ aclocal -I ${OECORE_TARGET_SYSROOT}/usr/share/aclocal [-I <replaceable>dir_containing_your_project-specific_m4_macros</replaceable>]
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$ autoconf
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$ autoheader
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$ automake -a
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</literallayout>
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</note>
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</para>
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</section>
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</section>
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<section id='makefile-based-projects'>
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<title>Makefile-Based Projects</title>
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<para>
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For Makefile-based projects, the cross-toolchain environment
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variables established by running the cross-toolchain environment
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setup script are subject to general <filename>make</filename>
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rules.
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</para>
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<para>
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To illustrate this, consider the following four cross-toolchain
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environment variables:
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<literallayout class='monospaced'>
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<ulink url='&YOCTO_DOCS_REF_URL;#var-CC'>CC</ulink>=i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/&DISTRO;/sysroots/i586-poky-linux
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<ulink url='&YOCTO_DOCS_REF_URL;#var-LD'>LD</ulink>=i586-poky-linux-ld --sysroot=/opt/poky/&DISTRO;/sysroots/i586-poky-linux
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<ulink url='&YOCTO_DOCS_REF_URL;#var-CFLAGS'>CFLAGS</ulink>=-O2 -pipe -g -feliminate-unused-debug-types
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<ulink url='&YOCTO_DOCS_REF_URL;#var-CXXFLAGS'>CXXFLAGS</ulink>=-O2 -pipe -g -feliminate-unused-debug-types
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</literallayout>
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Now, consider the following three cases:
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<itemizedlist>
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<listitem><para>
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<emphasis>Case 1 - No Variables Set in the
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<filename>Makefile</filename>:</emphasis>
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Because these variables are not specifically set in the
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<filename>Makefile</filename>, the variables retain their
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values based on the environment.
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</para></listitem>
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<listitem><para>
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<emphasis>Case 2 - Variables Set in the
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<filename>Makefile</filename>:</emphasis>
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Specifically setting variables in the
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<filename>Makefile</filename> during the build results in
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the environment settings of the variables being
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overwritten.
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</para></listitem>
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<listitem><para>
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<emphasis>Case 3 - Variables Set when the
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<filename>Makefile</filename> is Executed from the
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Command Line:</emphasis>
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Executing the <filename>Makefile</filename> from the
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command-line results in the variables being overwritten
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with command-line content regardless of what is being set
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in the <filename>Makefile</filename>.
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In this case, environment variables are not considered
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unless you use the "-e" flag during the build:
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<literallayout class='monospaced'>
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$ make -e <replaceable>file</replaceable>
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</literallayout>
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If you use this flag, then the environment values of the
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variables override any variables specifically set in the
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<filename>Makefile</filename>.
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</para></listitem>
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</itemizedlist>
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<note>
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For the list of variables set up by the cross-toolchain
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environment setup script, see the
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"<link linkend='sdk-running-the-sdk-environment-setup-script'>Running the SDK Environment Setup Script</link>"
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section.
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</note>
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</para>
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</section>
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</chapter>
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<!--
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vim: expandtab tw=80 ts=4
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-->
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