Yocto 2.5
Move OpenBMC to Yocto 2.5(sumo)
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Change-Id: I5c5ad6904a16e14c1c397f0baf10c9d465594a78
diff --git a/import-layers/yocto-poky/documentation/sdk-manual/sdk-working-projects.xml b/import-layers/yocto-poky/documentation/sdk-manual/sdk-working-projects.xml
index 6965e3f..d8cc422 100644
--- a/import-layers/yocto-poky/documentation/sdk-manual/sdk-working-projects.xml
+++ b/import-layers/yocto-poky/documentation/sdk-manual/sdk-working-projects.xml
@@ -8,7 +8,7 @@
<para>
You can use the SDK toolchain directly with Makefile,
- Autotools, and <trademark class='trade'>Eclipse</trademark> based
+ Autotools, and <trademark class='trade'>Eclipse</trademark>-based
projects.
This chapter covers the first two, while the
"<link linkend='sdk-eclipse-project'>Developing Applications Using <trademark class='trade'>Eclipse</trademark></link>"
@@ -19,263 +19,494 @@
<title>Autotools-Based Projects</title>
<para>
- Once you have a suitable cross-toolchain installed, it is very easy
- to develop a project outside of the OpenEmbedded build system.
- This section presents a simple "Helloworld" example that shows how
- to set up, compile, and run the project.
+ Once you have a suitable
+ <ulink url='&YOCTO_DOCS_REF_URL;#cross-development-toolchain'>cross-development toolchain</ulink>
+ installed, it is very easy to develop a project using the
+ <ulink url='https://en.wikipedia.org/wiki/GNU_Build_System'>GNU Autotools-based</ulink>
+ workflow, which is outside of the
+ <ulink url='&YOCTO_DOCS_REF_URL;#build-system-term'>OpenEmbedded build system</ulink>.
</para>
- <section id='creating-and-running-a-project-based-on-gnu-autotools'>
- <title>Creating and Running a Project Based on GNU Autotools</title>
+ <para>
+ The following figure presents a simple Autotools workflow.
+ <imagedata fileref="figures/sdk-autotools-flow.png" width="7in" height="8in" align="center" />
+ </para>
- <para>
- Follow these steps to create a simple Autotools-based project:
- <orderedlist>
- <listitem><para>
- <emphasis>Create your directory:</emphasis>
- Create a clean directory for your project and then make
- that directory your working location:
- <literallayout class='monospaced'>
+ <para>
+ Follow these steps to create a simple Autotools-based
+ "Hello World" project:
+ <note>
+ For more information on the GNU Autotools workflow,
+ see the same example on the
+ <ulink url='https://developer.gnome.org/anjuta-build-tutorial/stable/create-autotools.html.en'>GNOME Developer</ulink>
+ site.
+ </note>
+ <orderedlist>
+ <listitem><para>
+ <emphasis>Create a Working Directory and Populate It:</emphasis>
+ Create a clean directory for your project and then make
+ that directory your working location.
+ <literallayout class='monospaced'>
$ mkdir $HOME/helloworld
$ cd $HOME/helloworld
- </literallayout>
- </para></listitem>
- <listitem><para>
- <emphasis>Populate the directory:</emphasis>
- Create <filename>hello.c</filename>,
- <filename>Makefile.am</filename>,
- and <filename>configure.ac</filename> files as follows:
- <itemizedlist>
- <listitem><para>
- For <filename>hello.c</filename>, include
- these lines:
- <literallayout class='monospaced'>
+ </literallayout>
+ After setting up the directory, populate it with files
+ needed for the flow.
+ You need a project source file, a file to help with
+ configuration, and a file to help create the Makefile,
+ and a README file:
+ <filename>hello.c</filename>,
+ <filename>configure.ac</filename>,
+ <filename>Makefile.am</filename>, and
+ <filename>README</filename>, respectively.</para>
+
+ <para> Use the following command to create an empty README
+ file, which is required by GNU Coding Standards:
+ <literallayout class='monospaced'>
+ $ touch README
+ </literallayout>
+ Create the remaining three files as follows:
+ <itemizedlist>
+ <listitem><para>
+ <emphasis><filename>hello.c</filename>:</emphasis>
+ <literallayout class='monospaced'>
#include <stdio.h>
main()
{
printf("Hello World!\n");
}
- </literallayout>
- </para></listitem>
- <listitem><para>
- For <filename>Makefile.am</filename>,
- include these lines:
- <literallayout class='monospaced'>
- bin_PROGRAMS = hello
- hello_SOURCES = hello.c
- </literallayout>
- </para></listitem>
- <listitem><para>
- For <filename>configure.in</filename>,
- include these lines:
- <literallayout class='monospaced'>
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis><filename>configure.ac</filename>:</emphasis>
+ <literallayout class='monospaced'>
AC_INIT(hello,0.1)
AM_INIT_AUTOMAKE([foreign])
AC_PROG_CC
- AC_PROG_INSTALL
- AC_OUTPUT(Makefile)
- </literallayout>
- </para></listitem>
- </itemizedlist>
- </para></listitem>
- <listitem><para>
- <emphasis>Source the cross-toolchain
- environment setup file:</emphasis>
- As described earlier in the manual, installing the
- cross-toolchain creates a cross-toolchain
- environment setup script in the directory that the SDK
- was installed.
- Before you can use the tools to develop your project,
- you must source this setup script.
- The script begins with the string "environment-setup"
- and contains the machine architecture, which is
- followed by the string "poky-linux".
- Here is an example that sources a script from the
- default SDK installation directory that uses the
- 32-bit Intel x86 Architecture and the
- &DISTRO_NAME; Yocto Project release:
- <literallayout class='monospaced'>
+ AC_CONFIG_FILES(Makefile)
+ AC_OUTPUT
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis><filename>Makefile.am</filename>:</emphasis>
+ <literallayout class='monospaced'>
+ bin_PROGRAMS = hello
+ hello_SOURCES = hello.c
+ </literallayout>
+ </para></listitem>
+ </itemizedlist>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Source the Cross-Toolchain
+ Environment Setup File:</emphasis>
+ As described earlier in the manual, installing the
+ cross-toolchain creates a cross-toolchain
+ environment setup script in the directory that the SDK
+ was installed.
+ Before you can use the tools to develop your project,
+ you must source this setup script.
+ The script begins with the string "environment-setup"
+ and contains the machine architecture, which is
+ followed by the string "poky-linux".
+ For this example, the command sources a script from the
+ default SDK installation directory that uses the
+ 32-bit Intel x86 Architecture and the
+ &DISTRO_NAME; Yocto Project release:
+ <literallayout class='monospaced'>
$ source /opt/poky/&DISTRO;/environment-setup-i586-poky-linux
- </literallayout>
- </para></listitem>
- <listitem><para>
- <emphasis>Generate the local aclocal.m4
- files and create the configure script:</emphasis>
- The following GNU Autotools generate the local
- <filename>aclocal.m4</filename> files and create the
- configure script:
- <literallayout class='monospaced'>
- $ aclocal
- $ autoconf
- </literallayout>
- </para></listitem>
- <listitem><para>
- <emphasis>Generate files needed by GNU coding
- standards:</emphasis>
- GNU coding standards require certain files in order
- for the project to be compliant.
- This command creates those files:
- <literallayout class='monospaced'>
- $ touch NEWS README AUTHORS ChangeLog
- </literallayout>
- </para></listitem>
- <listitem><para>
- <emphasis>Generate the configure file:</emphasis>
- This command generates the
- <filename>configure</filename>:
- <literallayout class='monospaced'>
- $ automake -a
- </literallayout>
- </para></listitem>
- <listitem><para>
- <emphasis>Cross-compile the project:</emphasis>
- This command compiles the project using the
- cross-compiler.
- The
- <ulink url='&YOCTO_DOCS_REF_URL;#var-CONFIGURE_FLAGS'><filename>CONFIGURE_FLAGS</filename></ulink>
- environment variable provides the minimal arguments for
- GNU configure:
- <literallayout class='monospaced'>
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Create the <filename>configure</filename> Script:</emphasis>
+ Use the <filename>autoreconf</filename> command to
+ generate the <filename>configure</filename> script.
+ <literallayout class='monospaced'>
+ $ autoreconf
+ </literallayout>
+ The <filename>autoreconf</filename> tool takes care
+ of running the other Autotools such as
+ <filename>aclocal</filename>,
+ <filename>autoconf</filename>, and
+ <filename>automake</filename>.
+ <note>
+ If you get errors from
+ <filename>configure.ac</filename>, which
+ <filename>autoreconf</filename> runs, that indicate
+ missing files, you can use the "-i" option, which
+ ensures missing auxiliary files are copied to the build
+ host.
+ </note>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Cross-Compile the Project:</emphasis>
+ This command compiles the project using the
+ cross-compiler.
+ The
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-CONFIGURE_FLAGS'><filename>CONFIGURE_FLAGS</filename></ulink>
+ environment variable provides the minimal arguments for
+ GNU configure:
+ <literallayout class='monospaced'>
$ ./configure ${CONFIGURE_FLAGS}
- </literallayout>
- </para></listitem>
- <listitem><para>
- <emphasis>Make and install the project:</emphasis>
- These two commands generate and install the project
- into the destination directory:
- <literallayout class='monospaced'>
+ </literallayout>
+ For an Autotools-based project, you can use the
+ cross-toolchain by just passing the appropriate host
+ option to <filename>configure.sh</filename>.
+ The host option you use is derived from the name of the
+ environment setup script found in the directory in which
+ you installed the cross-toolchain.
+ For example, the host option for an ARM-based target that
+ uses the GNU EABI is
+ <filename>armv5te-poky-linux-gnueabi</filename>.
+ You will notice that the name of the script is
+ <filename>environment-setup-armv5te-poky-linux-gnueabi</filename>.
+ Thus, the following command works to update your project
+ and rebuild it using the appropriate cross-toolchain tools:
+ <literallayout class='monospaced'>
+ $ ./configure --host=armv5te-poky-linux-gnueabi --with-libtool-sysroot=<replaceable>sysroot_dir</replaceable>
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Make and Install the Project:</emphasis>
+ These two commands generate and install the project
+ into the destination directory:
+ <literallayout class='monospaced'>
$ make
$ make install DESTDIR=./tmp
- </literallayout>
- </para></listitem>
- <listitem><para>
- <emphasis>Verify the installation:</emphasis>
- This command is a simple way to verify the installation
- of your project.
- Running the command prints the architecture on which
- the binary file can run.
- This architecture should be the same architecture that
- the installed cross-toolchain supports.
- <literallayout class='monospaced'>
- $ file ./tmp/usr/local/bin/hello
- </literallayout>
- </para></listitem>
- <listitem><para>
- <emphasis>Execute your project:</emphasis>
- To execute the project in the shell, simply enter
- the name.
- You could also copy the binary to the actual target
- hardware and run the project there as well:
- <literallayout class='monospaced'>
- $ ./hello
- </literallayout>
- As expected, the project displays the "Hello World!"
- message.
- </para></listitem>
- </orderedlist>
- </para>
- </section>
-
- <section id='passing-host-options'>
- <title>Passing Host Options</title>
-
- <para>
- For an Autotools-based project, you can use the cross-toolchain
- by just passing the appropriate host option to
- <filename>configure.sh</filename>.
- The host option you use is derived from the name of the
- environment setup script found in the directory in which you
- installed the cross-toolchain.
- For example, the host option for an ARM-based target that uses
- the GNU EABI is <filename>armv5te-poky-linux-gnueabi</filename>.
- You will notice that the name of the script is
- <filename>environment-setup-armv5te-poky-linux-gnueabi</filename>.
- Thus, the following command works to update your project and
- rebuild it using the appropriate cross-toolchain tools:
- <literallayout class='monospaced'>
- $ ./configure --host=armv5te-poky-linux-gnueabi \
- --with-libtool-sysroot=<replaceable>sysroot_dir</replaceable>
- </literallayout>
- <note>
- If the <filename>configure</filename> script results in
- problems recognizing the
- <filename>--with-libtool-sysroot=</filename><replaceable>sysroot-dir</replaceable>
- option, regenerate the script to enable the support by
- doing the following and then run the script again:
- <literallayout class='monospaced'>
- $ libtoolize --automake
- $ aclocal -I ${OECORE_TARGET_SYSROOT}/usr/share/aclocal [-I <replaceable>dir_containing_your_project-specific_m4_macros</replaceable>]
- $ autoconf
- $ autoheader
- $ automake -a
</literallayout>
- </note>
- </para>
- </section>
+ <note>
+ To learn about environment variables established
+ when you run the cross-toolchain environment setup
+ script and how they are used or overridden when
+ the Makefile, see the
+ "<link linkend='makefile-based-projects'>Makefile-Based Projects</link>"
+ section.
+ </note>
+ This next command is a simple way to verify the
+ installation of your project.
+ Running the command prints the architecture on which
+ the binary file can run.
+ This architecture should be the same architecture that
+ the installed cross-toolchain supports.
+ <literallayout class='monospaced'>
+ $ file ./tmp/usr/local/bin/hello
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Execute Your Project:</emphasis>
+ To execute the project, you would need to run it on your
+ target hardware.
+ If your target hardware happens to be your build host,
+ you could run the project as follows:
+ <literallayout class='monospaced'>
+ $ ./tmp/usr/local/bin/hello
+ </literallayout>
+ As expected, the project displays the "Hello World!"
+ message.
+ </para></listitem>
+ </orderedlist>
+ </para>
</section>
<section id='makefile-based-projects'>
<title>Makefile-Based Projects</title>
<para>
- For Makefile-based projects, the cross-toolchain environment
- variables established by running the cross-toolchain environment
- setup script are subject to general <filename>make</filename>
- rules.
+ Simple Makefile-based projects use and interact with the
+ cross-toolchain environment variables established when you run
+ the cross-toolchain environment setup script.
+ The environment variables are subject to general
+ <filename>make</filename> rules.
</para>
<para>
- To illustrate this, consider the following four cross-toolchain
- environment variables:
- <literallayout class='monospaced'>
- <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
- <ulink url='&YOCTO_DOCS_REF_URL;#var-LD'>LD</ulink>=i586-poky-linux-ld --sysroot=/opt/poky/&DISTRO;/sysroots/i586-poky-linux
- <ulink url='&YOCTO_DOCS_REF_URL;#var-CFLAGS'>CFLAGS</ulink>=-O2 -pipe -g -feliminate-unused-debug-types
- <ulink url='&YOCTO_DOCS_REF_URL;#var-CXXFLAGS'>CXXFLAGS</ulink>=-O2 -pipe -g -feliminate-unused-debug-types
- </literallayout>
- Now, consider the following three cases:
+ This section presents a simple Makefile development flow and
+ provides an example that lets you see how you can use
+ cross-toolchain environment variables and Makefile variables
+ during development.
+ <imagedata fileref="figures/sdk-makefile-flow.png" width="6in" height="7in" align="center" />
+ </para>
+
+ <para>
+ The main point of this section is to explain the following three
+ cases regarding variable behavior:
<itemizedlist>
<listitem><para>
<emphasis>Case 1 - No Variables Set in the
- <filename>Makefile</filename>:</emphasis>
- Because these variables are not specifically set in the
+ <filename>Makefile</filename> Map to Equivalent
+ Environment Variables Set in the SDK Setup Script:</emphasis>
+ Because matching variables are not specifically set in the
<filename>Makefile</filename>, the variables retain their
- values based on the environment.
+ values based on the environment setup script.
</para></listitem>
<listitem><para>
- <emphasis>Case 2 - Variables Set in the
- <filename>Makefile</filename>:</emphasis>
- Specifically setting variables in the
+ <emphasis>Case 2 - Variables Are Set in the Makefile that
+ Map to Equivalent Environment Variables from the SDK
+ Setup Script:</emphasis>
+ Specifically setting matching variables in the
<filename>Makefile</filename> during the build results in
the environment settings of the variables being
overwritten.
+ In this case, the variables you set in the
+ <filename>Makefile</filename> are used.
</para></listitem>
<listitem><para>
- <emphasis>Case 3 - Variables Set when the
- <filename>Makefile</filename> is Executed from the
- Command Line:</emphasis>
+ <emphasis>Case 3 - Variables Are Set Using the Command Line
+ that Map to Equivalent Environment Variables from the
+ SDK Setup Script:</emphasis>
Executing the <filename>Makefile</filename> from the
- command-line results in the variables being overwritten
- with command-line content regardless of what is being set
- in the <filename>Makefile</filename>.
- In this case, environment variables are not considered
- unless you use the "-e" flag during the build:
- <literallayout class='monospaced'>
- $ make -e <replaceable>file</replaceable>
- </literallayout>
- If you use this flag, then the environment values of the
- variables override any variables specifically set in the
- <filename>Makefile</filename>.
+ command line results in the environment variables being
+ overwritten.
+ In this case, the command-line content is used.
</para></listitem>
</itemizedlist>
<note>
- For the list of variables set up by the cross-toolchain
- environment setup script, see the
- "<link linkend='sdk-running-the-sdk-environment-setup-script'>Running the SDK Environment Setup Script</link>"
- section.
+ Regardless of how you set your variables, if you use
+ the "-e" option with <filename>make</filename>, the
+ variables from the SDK setup script take precedence:
+ <literallayout class='monospaced'>
+ $ make -e <replaceable>target</replaceable>
+ </literallayout>
</note>
</para>
+
+ <para>
+ The remainder of this section presents a simple Makefile example
+ that demonstrates these variable behaviors.
+ </para>
+
+ <para>
+ In a new shell environment variables are not established for the
+ SDK until you run the setup script.
+ For example, the following commands show a null value for the
+ compiler variable (i.e.
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-CC'><filename>CC</filename></ulink>).
+ <literallayout class='monospaced'>
+ $ echo ${CC}
+
+ $
+ </literallayout>
+ Running the SDK setup script for a 64-bit build host and an
+ i586-tuned target architecture for a
+ <filename>core-image-sato</filename> image using the current
+ &DISTRO; Yocto Project release and then echoing that variable
+ shows the value established through the script:
+ <literallayout class='monospaced'>
+ $ source /opt/poky/&DISTRO;/environment-setup-i586-poky-linux
+ $ echo ${CC}
+ i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux
+ </literallayout>
+ </para>
+
+ <para>
+ To illustrate variable use, work through this simple "Hello World!"
+ example:
+ <orderedlist>
+ <listitem><para>
+ <emphasis>Create a Working Directory and Populate It:</emphasis>
+ Create a clean directory for your project and then make
+ that directory your working location.
+ <literallayout class='monospaced'>
+ $ mkdir $HOME/helloworld
+ $ cd $HOME/helloworld
+ </literallayout>
+ After setting up the directory, populate it with files
+ needed for the flow.
+ You need a <filename>main.c</filename> file from which you
+ call your function, a <filename>module.h</filename> file
+ to contain headers, and a <filename>module.c</filename>
+ that defines your function.
+ </para>
+
+ <para>Create the three files as follows:
+ <itemizedlist>
+ <listitem><para>
+ <emphasis><filename>main.c</filename>:</emphasis>
+ <literallayout class='monospaced'>
+ #include "module.h"
+ void sample_func();
+ int main()
+ {
+ sample_func();
+ return 0;
+ }
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis><filename>module.h</filename>:</emphasis>
+ <literallayout class='monospaced'>
+ #include <stdio.h>
+ void sample_func();
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis><filename>module.c</filename>:</emphasis>
+ <literallayout class='monospaced'>
+ #include "module.h"
+ void sample_func()
+ {
+ printf("Hello World!");
+ printf("\n");
+ }
+ </literallayout>
+ </para></listitem>
+ </itemizedlist>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Source the Cross-Toolchain Environment Setup File:</emphasis>
+ As described earlier in the manual, installing the
+ cross-toolchain creates a cross-toolchain environment setup
+ script in the directory that the SDK was installed.
+ Before you can use the tools to develop your project,
+ you must source this setup script.
+ The script begins with the string "environment-setup"
+ and contains the machine architecture, which is
+ followed by the string "poky-linux".
+ For this example, the command sources a script from the
+ default SDK installation directory that uses the
+ 32-bit Intel x86 Architecture and the
+ &DISTRO_NAME; Yocto Project release:
+ <literallayout class='monospaced'>
+ $ source /opt/poky/&DISTRO;/environment-setup-i586-poky-linux
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Create the <filename>Makefile</filename>:</emphasis>
+ For this example, the Makefile contains two lines that
+ can be used to set the <filename>CC</filename> variable.
+ One line is identical to the value that is set when you
+ run the SDK environment setup script, and the other line
+ sets <filename>CC</filename> to "gcc", the default GNU
+ compiler on the build host:
+ <literallayout class='monospaced'>
+ # CC=i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux
+ # CC="gcc"
+ all: main.o module.o
+ ${CC} main.o module.o -o target_bin
+ main.o: main.c module.h
+ ${CC} -I . -c main.c
+ module.o: module.c module.h
+ ${CC} -I . -c module.c
+ clean:
+ rm -rf *.o
+ rm target_bin
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Make the Project:</emphasis>
+ Use the <filename>make</filename> command to create the
+ binary output file.
+ Because variables are commented out in the Makefile,
+ the value used for <filename>CC</filename> is the value
+ set when the SDK environment setup file was run:
+ <literallayout class='monospaced'>
+ $ make
+ i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux -I . -c main.c
+ i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux -I . -c module.c
+ i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux main.o module.o -o target_bin
+ </literallayout>
+ From the results of the previous command, you can see that
+ the compiler used was the compiler established through
+ the <filename>CC</filename> variable defined in the
+ setup script.</para>
+
+ <para>You can override the <filename>CC</filename>
+ environment variable with the same variable as set from
+ the Makefile by uncommenting the line in the Makefile
+ and running <filename>make</filename> again.
+ <literallayout class='monospaced'>
+ $ make clean
+ rm -rf *.o
+ rm target_bin
+ #
+ # Edit the Makefile by uncommenting the line that sets CC to "gcc"
+ #
+ $ make
+ gcc -I . -c main.c
+ gcc -I . -c module.c
+ gcc main.o module.o -o target_bin
+ </literallayout>
+ As shown in the previous example, the cross-toolchain
+ compiler is not used.
+ Rather, the default compiler is used.</para>
+
+ <para>This next case shows how to override a variable
+ by providing the variable as part of the command line.
+ Go into the Makefile and re-insert the comment character
+ so that running <filename>make</filename> uses
+ the established SDK compiler.
+ However, when you run <filename>make</filename>, use a
+ command-line argument to set <filename>CC</filename>
+ to "gcc":
+ <literallayout class='monospaced'>
+ $ make clean
+ rm -rf *.o
+ rm target_bin
+ #
+ # Edit the Makefile to comment out the line setting CC to "gcc"
+ #
+ $ make
+ i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux -I . -c main.c
+ i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux -I . -c module.c
+ i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux main.o module.o -o target_bin
+ $ make clean
+ rm -rf *.o
+ rm target_bin
+ $ make CC="gcc"
+ gcc -I . -c main.c
+ gcc -I . -c module.c
+ gcc main.o module.o -o target_bin
+ </literallayout>
+ In the previous case, the command-line argument overrides
+ the SDK environment variable.</para>
+
+ <para>In this last case, edit Makefile again to use the
+ "gcc" compiler but then use the "-e" option on the
+ <filename>make</filename> command line:
+ <literallayout class='monospaced'>
+ $ make clean
+ rm -rf *.o
+ rm target_bin
+ #
+ # Edit the Makefile to use "gcc"
+ #
+ $ make
+ gcc -I . -c main.c
+ gcc -I . -c module.c
+ gcc main.o module.o -o target_bin
+ $ make clean
+ rm -rf *.o
+ rm target_bin
+ $ make -e
+ i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux -I . -c main.c
+ i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux -I . -c module.c
+ i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux main.o module.o -o target_bin
+ </literallayout>
+ In the previous case, the "-e" option forces
+ <filename>make</filename> to use the SDK environment
+ variables regardless of the values in the Makefile.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Execute Your Project:</emphasis>
+ To execute the project (i.e.
+ <filename>target_bin</filename>), use the following
+ command:
+ <literallayout class='monospaced'>
+ $ ./target_bin
+ Hello World!
+ </literallayout>
+ <note>
+ If you used the cross-toolchain compiler to build
+ <filename>target_bin</filename> and your build host
+ differs in architecture from that of the target
+ machine, you need to run your project on the target
+ device.
+ </note>
+ As expected, the project displays the "Hello World!"
+ message.
+ </para></listitem>
+ </orderedlist>
+ </para>
</section>
</chapter>
<!--