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-rw-r--r--documentation/ref-manual/ref-variables.xml37
1 files changed, 25 insertions, 12 deletions
diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 137a556d92..09eb9b9dfc 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -10701,27 +10701,40 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
10701 <glossdef> 10701 <glossdef>
10702 <para role="glossdeffirst"> 10702 <para role="glossdeffirst">
10703<!-- <para role="glossdeffirst"><imagedata fileref="figures/define-generic.png" /> --> 10703<!-- <para role="glossdeffirst"><imagedata fileref="figures/define-generic.png" /> -->
10704 If multiple recipes provide an item, this variable 10704 If multiple recipes provide the same item, this variable
10705 determines which recipe should be given preference. 10705 determines which recipe is preferred and thus provides
10706 You should always suffix the variable with the name of the 10706 the item (i.e. the preferred provider).
10707 provided item, and you should set it to the 10707 You should always suffix this variable with the name of the
10708 <link linkend='var-PN'><filename>PN</filename></link> 10708 provided item.
10709 of the recipe to which you want to give precedence. 10709 And, you should define the variable using the preferred
10710 Some examples: 10710 recipe's name
10711 (<link linkend='var-PN'><filename>PN</filename></link>).
10712 Here is a common example:
10711 <literallayout class='monospaced'> 10713 <literallayout class='monospaced'>
10712 PREFERRED_PROVIDER_virtual/kernel ?= "linux-yocto" 10714 PREFERRED_PROVIDER_virtual/kernel ?= "linux-yocto"
10715 </literallayout>
10716 In the previous example, multiple recipes are providing
10717 "virtual/kernel".
10718 The <filename>PREFERRED_PROVIDER</filename> variable is
10719 set with the name (<filename>PN</filename>) of the recipe
10720 you prefer to provide "virtual/kernel".
10721 </para>
10722
10723 <para>
10724 Following are more examples:
10725 <literallayout class='monospaced'>
10713 PREFERRED_PROVIDER_virtual/xserver = "xserver-xf86" 10726 PREFERRED_PROVIDER_virtual/xserver = "xserver-xf86"
10714 PREFERRED_PROVIDER_virtual/libgl ?= "mesa" 10727 PREFERRED_PROVIDER_virtual/libgl ?= "mesa"
10715 </literallayout> 10728 </literallayout>
10716 For more information, see the 10729 For more information, see the
10717 "<ulink url='&YOCTO_DOCS_CM_URL;#metadata-virtual-providers'>Metadata (Virtual Providers)</ulink>" 10730 "<ulink url='&YOCTO_DOCS_DEV_URL;#metadata-virtual-providers'>Using Virtual Providers</ulink>"
10718 section in the Yocto Project Concepts Manual. 10731 section in the Yocto Project Development Tasks Manual.
10719 <note> 10732 <note>
10720 If you set <filename>PREFERRED_PROVIDER</filename> 10733 If you use a <filename>virtual/*</filename> item
10721 for a <filename>virtual/*</filename> item, then any 10734 with <filename>PREFERRED_PROVIDER</filename>, then any
10722 recipe that 10735 recipe that
10723 <link linkend='var-PROVIDES'><filename>PROVIDES</filename></link> 10736 <link linkend='var-PROVIDES'><filename>PROVIDES</filename></link>
10724 that item that is not selected by 10737 that item but is not selected (defined) by
10725 <filename>PREFERRED_PROVIDER</filename> is prevented 10738 <filename>PREFERRED_PROVIDER</filename> is prevented
10726 from building, which is usually desirable since this 10739 from building, which is usually desirable since this
10727 mechanism is designed to select between mutually 10740 mechanism is designed to select between mutually