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author | Michael 'Mickey' Lauer <mickey@vanille-media.de> | 2009-02-25 01:47:30 +0100 |
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committer | Michael 'Mickey' Lauer <mickey@vanille-media.de> | 2009-02-25 01:47:30 +0100 |
commit | 25b51d32c982a6767f3d4a88dec12f70c8c8f875 (patch) | |
tree | 206e94d12d2fda511c5b383adfec3684829703a1 /docs/usermanual/reference/class_siteinfo.xml | |
parent | 6d76191b2021518d2f1ea00c20a1ec3151d93069 (diff) |
docs: import usermanual from org.openembedded.documentation.
org.openembedded.documentation is deprecated now; please do all updates here!
Diffstat (limited to 'docs/usermanual/reference/class_siteinfo.xml')
-rw-r--r-- | docs/usermanual/reference/class_siteinfo.xml | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/docs/usermanual/reference/class_siteinfo.xml b/docs/usermanual/reference/class_siteinfo.xml new file mode 100644 index 0000000000..4d66e85e7c --- /dev/null +++ b/docs/usermanual/reference/class_siteinfo.xml @@ -0,0 +1,180 @@ +<?xml version="1.0" encoding="UTF-8"?> +<section id="siteinfo_class" xreflabel="siteinfo class"> + <title>siteinfo class</title> + + <para>The siteinfo class provides information for a target with a particular + emphasis on determining the names of the site files to be passed to + autoconf, as described in the <xref linkend="autotools_class" />. Full site + information for your target can be determined by looking at the table in the + class implementation found in the + <command>classes/siteinfo.bbclass</command> file. A typical entry contains + the name of the target and a list of site information for the + target:<screen> "sh4-linux": "endian-little bit-32 common-glibc sh-common",</screen>In + the above example for sh4-linux target (that's a build for an sh4 processor + using glibc) we see that the endianess and bit-size of target are defined + and an additional set of site files that should be used are listed. These + include a common site file for glibc and a common site file for sh + processors (so sh3 and sh4 can share defines). A <command>"common"</command> + entry is automatically added to the end of each of the definitions during + processing.</para> + + <para>The class makes available three variables based on the information + provided for a target:</para> + + <variablelist> + <varlistentry> + <term>SITEINFO_ENDIANESS</term> + + <listitem> + <para>Defines the endianess of the target as either + <command>"le"</command> (little endian) or <command>"be"</command> + (big endian). The target must list either + <command>endian-little</command> or <command>endian-big</command> in + it's site information.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term>SITEINFO_BITS</term> + + <listitem> + <para>Defines the bitsize of the target as either + <command>"32"</command> or <command>"64"</command>. The target must + list either <command>bit-32</command> or <command>bit-64</command> in + it's site information.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term>CONFIG_SITE</term> + + <listitem> + <para>Defines the site files to be used by autoconf. This is a space + separated list of one or more site files for the target.</para> + </listitem> + </varlistentry> + </variablelist> + + <para>A typical use for the <command>SITEINFO_ENDIANESS</command> and + <command>SITEINFO_BITS</command> variables is to provide configuration + within a recipe based on their values. The following example from the + <emphasis>openssl</emphasis> recipe showw the correct define for the + endiness of the target being passed to openssl via the compiler flags. The + define to add to the flags is set based on the value of the + <command>SITEINFO_ENDIANESS</command> variable. Note that use of the + <emphasis>base_conditional</emphasis> method (see the <xref + linkend="recipes_advanced_python" /> section) to select a value conditional + on the endianess setting:</para> + + <para><screen> # Additional flag based on target endiness (see siteinfo.bbclass) + CFLAG="${CFLAG} ${@base_conditional('SITEINFO_ENDIANESS', 'le', '-DL_ENDIAN', '-DB_ENDIAN', d)}"</screen></para> + + <section> + <title>CONFIG_SITE: The autoconf site files</title> + + <para>The autotools configuration method has support for caching the + results of tests. In the cross-compilation case it is sometimes necessary + to prime the cache with per-calculated results (since tests designed to + run on the target cannot be run when cross-compiling). These are defined + via the site file(s) for the architecture you are using and may be + specific to the package you are building.</para> + + <para>Which site files are used is determined via the + <command>CONFIG_SITE</command> definition which is calculated via the + siteinfo class. Typically the following site files will be checked for, + and used in the order found:</para> + + <variablelist> + <varlistentry> + <term>endian-(big|little)</term> + + <listitem> + <para>Either <command>endian-big</command> or + <command>endian-little</command> depending on the endianess of the + target. This site file would contain defines that only change based + on if the target is little endian or big endian.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term>bit-(32|64)</term> + + <listitem> + <para>Either <command>bit-32</command> or <command>bit-64</command> + depending on the bitsize of the target. This site file would contain + defines that only change based on if the target is a 32-bit or + 64-bit cpu.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term>common-(libc|uclibc)</term> + + <listitem> + <para>Either <command>common-libc</command> or + <command>common-uclibc</command> based on the C library being used + for the target. This site file would contain defines the are + specific to the C library being used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><arch>-common</term> + + <listitem> + <para>A common site file for the target architecture. For i386, + i485, i586 and i686 this would be <command>x86-common</command>, for + sh3 and sh4 this would be <command>sh-common</command> and for + various arm targets this would be + <command>arm-common</command>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term>common</term> + + <listitem> + <para>This is a site file which is common for all targets and + contains definitions which remain the same no matter what target is + being built.</para> + </listitem> + </varlistentry> + </variablelist> + + <para>Each of the supported site files for a target is will be checked for + in several different directories. Each time a file is found it as added to + the list of files in the <command>CONFIG_SITE</command> variable. The + following directories are checked:</para> + + <variablelist> + <varlistentry> + <term>org.openembedded.dev/packages/<packagename>/site-<version>/</term> + + <listitem> + <para>This directory is for site files which are specific to a + particular version (where version is the PV of the package) of a + package.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term>org.openembedded.dev/packages/<packagename>/site/</term> + + <listitem> + <para>This directory is for site files which are specific to a + particular package, but apply to all versions of the package.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term>org.openembedded.dev/site/</term> + + <listitem> + <para>This directory is for site files that are common to all + packages. Originally this was the only site file directory that was + supported.</para> + </listitem> + </varlistentry> + </variablelist> + </section> +</section>
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