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author | Scott Rifenbark <scott.m.rifenbark@intel.com> | 2012-03-06 10:37:59 -0600 |
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committer | Richard Purdie <richard.purdie@linuxfoundation.org> | 2012-03-08 12:08:08 -0800 |
commit | ae647f6032f6f637829adb2eba896ec924eacb29 (patch) | |
tree | 1dd9ce45dc15bd0b4642f27e67c84b45f60a5fa2 /documentation/dev-manual | |
parent | 1084bc5d77c430e8fd8c3d26a5c5ec0cda24aca3 (diff) | |
download | ast2050-yocto-poky-ae647f6032f6f637829adb2eba896ec924eacb29.zip ast2050-yocto-poky-ae647f6032f6f637829adb2eba896ec924eacb29.tar.gz |
documentation/dev-manual/dev-manual-common-tasks.xml: Review comments
Applied the review comments from Paul Eggleton for the new section
on "Understanding and Using Layers."
(From yocto-docs rev: 6bf5854dd355afdbc01c4c4fb94a4062bd9eae20)
Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Diffstat (limited to 'documentation/dev-manual')
-rw-r--r-- | documentation/dev-manual/dev-manual-common-tasks.xml | 90 |
1 files changed, 48 insertions, 42 deletions
diff --git a/documentation/dev-manual/dev-manual-common-tasks.xml b/documentation/dev-manual/dev-manual-common-tasks.xml index 9f7d042..4702ae9 100644 --- a/documentation/dev-manual/dev-manual-common-tasks.xml +++ b/documentation/dev-manual/dev-manual-common-tasks.xml @@ -77,7 +77,8 @@ you need. You can see the <ulink url='http://www.openembedded.org/wiki/LayerIndex'><filename>LayerIndex</filename></ulink> - to determine what types of layers already exist in the Yocto Project.</para></listitem> + for a list of layers from the OpenEmbedded community that can be used in the + Yocto Project.</para></listitem> <listitem><para><emphasis>Create a Directory:</emphasis> Create the directory for your layer. Traditionally, prepend the name of the folder with the string @@ -113,12 +114,14 @@ variable is then appended with the layer name. The <filename><ulink url='http://www.yoctoproject.org/docs/latest/poky-ref-manual/poky-ref-manual.html#var-BBFILE_PATTERN'>BBFILE_PATTERN</ulink></filename> - variable immediately expands with a regular expression used to match files from - <filename>BBFILES</filename> into a particular layer, in this case by using - the base pathname. + variable is set to a regular expression and is used to match files + from <filename>BBFILES</filename> into a particular layer. + In this case, immediate expansion of + <filename><ulink url='http://www.yoctoproject.org/docs/latest/poky-ref-manual/poky-ref-manual.html#var-LAYERDIR'>LAYERDIR</ulink></filename> + sets <filename>BBFILES_PATTERN</filename> to the layer's path. The <filename><ulink url='http://www.yoctoproject.org/docs/latest/poky-ref-manual/poky-ref-manual.html#var-BBFILE_PRIORITY'>BBFILE_PRIORITY</ulink></filename> - variable then assigns different priorities to the files in different layers. + variable then assigns a priority to the layer. Applying priorities is useful in situations where the same package might appear in multiple layers and allows you to choose what layer should take precedence.</para> <para>Note the use of the @@ -127,8 +130,9 @@ The <filename>LAYERDIR</filename> variable expands to the directory of the current layer and requires the immediate expansion operator so that BitBake does not wait to expand the variable when it's parsing a different directory.</para> - <para>BitBake can locate where other <filename>.bbclass</filename> and configuration files - are applied through the <filename>BBPATH</filename> environment variable. + <para>BitBake locates included <filename>.bbclass</filename>, configuration, + and other files using the <filename>include</filename> and <filename>require</filename> + statements by way of the <filename>BBPATH</filename> environment variable. For these cases, BitBake uses the first file with the matching name found in <filename>BBPATH</filename>. This is similar to the way the <filename>PATH</filename> variable is used for binaries. @@ -218,9 +222,6 @@ During the processing of each <filename>conf/layer.conf</filename> file, BitBake adds the recipes, classes and configurations contained within the particular layer to the Yocto Project. - To create your own layer, independent of the Yocto Project files, - simply create a directory with a <filename>conf/layer.conf</filename> file and - add the directory to your <filename>bblayers.conf</filename> file. </para> </section> @@ -242,9 +243,9 @@ This means the original recipe and append file names are version number specific. If the underlying recipe is renamed to update to a newer version, the corresponding <filename>.bbappend</filename> file must be renamed as well. - During the build process, BitBake displays warnings on starting if it detects a + During the build process, BitBake displays an error on starting if it detects a <filename>.bbappend</filename> file that does not have an underlying recipe - with the proper name. + with a matching name. </para> <para> @@ -299,8 +300,10 @@ <literallayout class='monospaced'> FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" </literallayout> - Using the immediate expansion assignment operator <filename>:=</filename> and the trailing colon - are important so that the resulting list of pathnames is syntactically correct. + Using the immediate expansion assignment operator <filename>:=</filename> is important because + of the reference to <filename>THISDIR</filename>. + The trailing colon character is important as it ensures that items in the list remain + colon-separated. <note>BitBake automatically defines the <filename>THISDIR</filename> variable. You should never set this variable yourself. Using <filename>_prepend</filename> ensures your path will be searched prior to other @@ -358,37 +361,40 @@ Use the following form when running the layer management tool. <literallayout class='monospaced'> $ bitbake-layers <command> [arguments] - - Available commands: - flatten - flattens layer configuration into a separate output directory. - help - display general help or help on a specified command - show_appends - list bbappend files and recipe files they apply to - show_layers - show current configured layers - show_overlayed - list overlayed recipes (where there is a recipe in another layer that has a higher layer priority) - help - display general help or help on a specified command </literallayout> - </para> - - <para> - Flattening your layer configuration builds a "flattened" directory that contains - the contents of all layers, with any overlayed recipes removed and any - recipe append files (<filename>.bbappend</filename>) appended to the corresponding recipes. - You might have to perform some manual cleanup of the flattened layer as follows: + The following list describes the available commands: <itemizedlist> - <listitem><para>Non-recipe files (such as patches) are overwritten. - The flatten command shows a warning for these files.</para></listitem> - <listitem><para>Anything beyond the normal layer setup has been added to - the <filename>layer.conf</filename> file. - Only the lowest priority layer's <filename>layer.conf</filename> is used. + <listitem><para><filename><emphasis>flatten:</emphasis></filename> + Flattens the layer configuration into a separate output directory. + Flattening your layer configuration builds a "flattened" directory that contains + the contents of all layers, with any overlayed recipes removed and any + recipe append files (<filename>.bbappend</filename>) appended to the corresponding recipes. + You might have to perform some manual cleanup of the flattened layer as follows: + <itemizedlist> + <listitem><para>Non-recipe files (such as patches) are overwritten. + The flatten command shows a warning for these files.</para></listitem> + <listitem><para>Anything beyond the normal layer setup has been added to + the <filename>layer.conf</filename> file. + Only the lowest priority layer's <filename>layer.conf</filename> is used. + </para></listitem> + <listitem><para>Overridden and appended items from <filename>.bbappend</filename> + files need to be cleaned up. + For example, the contents of each <filename>.bbappend</filename> end up in the + flattened recipe. + However, if there are appended or changed variable values, you need to tidy + these up yourself.</para></listitem> + </itemizedlist></para></listitem> + <listitem><para><filename><emphasis>help:</emphasis></filename> + Displays general help or help on a specified command.</para></listitem> + <listitem><para><filename><emphasis>show_appends:</emphasis></filename> + Lists <filename>.bbappend</filename> files and the recipe files to which + they apply.</para></listitem> + <listitem><para><filename><emphasis>show_layers:</emphasis></filename> + Show the current configured layers.</para></listitem> + <listitem><para><filename><emphasis>show_overlayed:</emphasis></filename> + Lists overlayed recipes. + Overlayed recipes appear in another layer that has a higher layer priority. </para></listitem> - <listitem><para>Overridden and appended items from <filename>.bbappend</filename> - files never need to be cleaned up.</para></listitem> </itemizedlist> </para> </section> |