sysmo-bts
/
generic-poky
9
0
Fork 0
Code Pull Requests Releases Activity

adt-manual: Updated the Makefile-based project section. 

Fixes [YOCTO #7133]

Added more examples of how variables work in Makefile projects.

(From yocto-docs rev: e8aa42f3609de3dfe94c022d957b855a4f7ef032)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Scott Rifenbark 2015-04-14 06:49:55 -07:00 committed by Richard Purdie
parent 941910f47f
commit d654160eb2
1 changed files with 45 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
documentation/adt-manual/adt-command.xml
View File

@ -210,31 +210,55 @@
<title>Makefile-Based Projects</title>
<para>
For Makefile-based projects, the cross-toolchain environment
variables established by running the cross-toolchain environment
setup script override any settings you might have in your
<filename>Makefile</filename>.
For example, if you had settings such as the following in your
<filename>Makefile</filename>, the environment variables defined
by the script would override them:
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.
</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>=arm-poky-linux-gnueabi-gcc
<ulink url='&YOCTO_DOCS_REF_URL;#var-LD'>LD</ulink>=arm-poky-linux-gnueabi-ld
<ulink url='&YOCTO_DOCS_REF_URL;#var-CFLAGS'>CFLAGS</ulink>=”${CFLAGS} --sysroot=&lt;sysroot-dir&gt;”
<ulink url='&YOCTO_DOCS_REF_URL;#var-CXXFLAGS'>CXXFLAGS</ulink>=”${CXXFLAGS} --sysroot=&lt;sysroot-dir&gt;”
<ulink url='&YOCTO_DOCS_REF_URL;#var-CC'>CC</ulink>=i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/1.8/sysroots/i586-poky-linux
<ulink url='&YOCTO_DOCS_REF_URL;#var-LD'>LD</ulink>=i586-poky-linux-ld --sysroot=/opt/poky/1.8/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>
Consequently, you should not set variables like
<ulink url='&YOCTO_DOCS_REF_URL;#var-CC'><filename>CC</filename></ulink>
and
<ulink url='&YOCTO_DOCS_REF_URL;#var-LD'><filename>LD</filename></ulink>
in your <filename>Makefile</filename>.
For the list of variables set up by the cross-toolchain environment
setup script, see the
"<link linkend='setting-up-the-cross-development-environment'>Setting Up the Cross-Development Environment</link>"
section.
Now, consider the following three cases:
<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>, the variables retain their
values based on the environment.
</para></listitem>
<listitem><para><emphasis>Case 2 - Variables Set in the <filename>Makefile</filename>:</emphasis>
Specifically setting variables in the
<filename>Makefile</filename> during the build results in the
environment settings of the variables being overwritten.
</para></listitem>
<listitem><para><emphasis>Case 3 - Variables Set when the <filename>Makefile</filename> is Executed from the Command Line:</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>.
</para></listitem>
</itemizedlist>
<note>
For the list of variables set up by the cross-toolchain environment
setup script, see the
"<link linkend='setting-up-the-cross-development-environment'>Setting Up the Cross-Development Environment</link>"
section.
</note>
</para>
</section>
</chapter>
<!--
vim: expandtab tw=80 ts=4