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-rw-r--r--documentation/ref-manual/ref-variables.xml42
1 files changed, 40 insertions, 2 deletions
diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 433893b93d..ed735a7eb3 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -9571,8 +9571,46 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
9571 <glossdef> 9571 <glossdef>
9572 <para role="glossdeffirst"> 9572 <para role="glossdeffirst">
9573<!-- <para role="glossdeffirst"><imagedata fileref="figures/define-generic.png" /> --> 9573<!-- <para role="glossdeffirst"><imagedata fileref="figures/define-generic.png" /> -->
9574 The revision of the recipe. 9574 The revision of the recipe. The default value for this
9575 The default value for this variable is "r0". 9575 variable is "r0".
9576 Subsequent revisions of the recipe conventionally have the
9577 values "r1", "r2", and so forth.
9578 When
9579 <link linkend='var-PV'><filename>PV</filename></link>
9580 increases, <filename>PR</filename> is conventionally reset
9581 to "r0".
9582 <note>
9583 The OpenEmbedded build system does not need the aid of
9584 <filename>PR</filename> to know when to rebuild a
9585 recipe.
9586 The build system uses
9587 <link linkend='var-STAMP'><filename>STAMP</filename></link>
9588 and the
9589 <link linkend='shared-state-cache'>shared state cache</link>
9590 mechanisms.
9591 </note>
9592 The <filename>PR</filename> variable primarily becomes
9593 significant when a package manager dynamically installs
9594 packages on an already built image.
9595 In this case, <filename>PR</filename>, which is the default
9596 value of
9597 <link linkend='var-PKGR'><filename>PKGR</filename></link>,
9598 helps the package manager distinguish which package is the
9599 most recent one in cases where many packages have the same
9600 <filename>PV</filename> (i.e. <filename>PKGV</filename>).
9601 Packages have the same <filename>PV</filename> usually
9602 when the package manager installs the same upstream version
9603 and some of the packages include packaging fixes.
9604 <note>
9605 <filename>PR</filename> does not need to be increased
9606 for changes that do not change the package contents or
9607 metadata.
9608 </note>
9609 Because, manually managing <filename>PR</filename> can be
9610 cumbersome and error-prone, an automated solution exists.
9611 See the
9612 "<ulink url='&YOCTO_DOCS_DEV_URL;#working-with-a-pr-service'>Working With a PR Service</ulink>"
9613 section for more information.
9576 </para> 9614 </para>
9577 </glossdef> 9615 </glossdef>
9578 </glossentry> 9616 </glossentry>