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authorScott Rifenbark <scott.m.rifenbark@intel.com>2014-03-18 18:55:20 (GMT)
committerRichard Purdie <richard.purdie@linuxfoundation.org>2014-03-25 12:29:42 (GMT)
commit23da05febb0a0a48d21f61cc817872320628d840 (patch)
tree73c8ee5b8048ba14ed15ef437c533cde3a4b4aeb
parentc7fb9a6147b1c8ee3aa70061ac573a4040dbc207 (diff)
downloadpoky-23da05febb0a0a48d21f61cc817872320628d840.tar.gz
dev-manual: Read-through edits to "Understanding and Creating Layers".
Some minor edits applied. (From yocto-docs rev: 1897997ad3ef3ada76de77c7fb886fb624dcdfdb) Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
-rw-r--r--documentation/dev-manual/dev-manual-common-tasks.xml67
1 files changed, 38 insertions, 29 deletions
diff --git a/documentation/dev-manual/dev-manual-common-tasks.xml b/documentation/dev-manual/dev-manual-common-tasks.xml
index 092f2c1..1581059 100644
--- a/documentation/dev-manual/dev-manual-common-tasks.xml
+++ b/documentation/dev-manual/dev-manual-common-tasks.xml
@@ -64,8 +64,8 @@
64 the string <filename>meta-</filename>. 64 the string <filename>meta-</filename>.
65 <note> 65 <note>
66 It is not a requirement that a layer name begin with the 66 It is not a requirement that a layer name begin with the
67 prefix <filename>meta-</filename>, but it's a commonly accepted 67 prefix <filename>meta-</filename>, but it is a commonly
68 standard in the Yocto Project community. 68 accepted standard in the Yocto Project community.
69 </note> 69 </note>
70 For example, when you set up the Source Directory structure, 70 For example, when you set up the Source Directory structure,
71 you will see several layers: 71 you will see several layers:
@@ -194,8 +194,8 @@
194 variable then assigns a priority to the layer. 194 variable then assigns a priority to the layer.
195 Applying priorities is useful in situations 195 Applying priorities is useful in situations
196 where the same package might appear in multiple 196 where the same package might appear in multiple
197 layers and allows you to choose what layer 197 layers and allows you to choose the layer
198 should take precedence.</para></listitem> 198 that takes precedence.</para></listitem>
199 <listitem><para>The 199 <listitem><para>The
200 <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-LAYERVERSION'>LAYERVERSION</ulink></filename> 200 <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-LAYERVERSION'>LAYERVERSION</ulink></filename>
201 variable optionally specifies the version of a 201 variable optionally specifies the version of a
@@ -206,16 +206,17 @@
206 variable, which expands to the directory of the current 206 variable, which expands to the directory of the current
207 layer.</para> 207 layer.</para>
208 <para>Through the use of the <filename>BBPATH</filename> 208 <para>Through the use of the <filename>BBPATH</filename>
209 variable, BitBake locates <filename>.bbclass</filename> 209 variable, BitBake locates class files
210 files, configuration files, and files that are included 210 (<filename>.bbclass</filename>),
211 configuration files, and files that are included
211 with <filename>include</filename> and 212 with <filename>include</filename> and
212 <filename>require</filename> statements. 213 <filename>require</filename> statements.
213 For these cases, BitBake uses the first file that 214 For these cases, BitBake uses the first file that
214 matches the name found in <filename>BBPATH</filename>. 215 matches the name found in <filename>BBPATH</filename>.
215 This is similar to the way the <filename>PATH</filename> 216 This is similar to the way the <filename>PATH</filename>
216 variable is used for binaries. 217 variable is used for binaries.
217 We recommend, therefore, that you use unique 218 It is recommended, therefore, that you use unique
218 <filename>.bbclass</filename> and configuration 219 class and configuration
219 filenames in your custom layer.</para></listitem> 220 filenames in your custom layer.</para></listitem>
220 <listitem><para><emphasis>Add Content:</emphasis> Depending 221 <listitem><para><emphasis>Add Content:</emphasis> Depending
221 on the type of layer, add the content. 222 on the type of layer, add the content.
@@ -253,7 +254,8 @@
253 configuration. 254 configuration.
254 In other words, do not copy an entire recipe into your 255 In other words, do not copy an entire recipe into your
255 layer and then modify it. 256 layer and then modify it.
256 Rather, use <filename>.bbappend</filename> files to override 257 Rather, use an append file (<filename>.bbappend</filename>)
258 to override
257 only those parts of the original recipe you need to modify. 259 only those parts of the original recipe you need to modify.
258 </para> 260 </para>
259 </section> 261 </section>
@@ -263,7 +265,8 @@
263 265
264 <para> 266 <para>
265 Avoid duplicating include files. 267 Avoid duplicating include files.
266 Use <filename>.bbappend</filename> files for each recipe 268 Use append files (<filename>.bbappend</filename>)
269 for each recipe
267 that uses an include file. 270 that uses an include file.
268 Or, if you are introducing a new recipe that requires 271 Or, if you are introducing a new recipe that requires
269 the included file, use the path relative to the original 272 the included file, use the path relative to the original
@@ -285,7 +288,7 @@
285 However, OpenEmbedded's layer <filename>meta-oe</filename> 288 However, OpenEmbedded's layer <filename>meta-oe</filename>
286 does. 289 does.
287 Consequently, <filename>meta-oe</filename> uses 290 Consequently, <filename>meta-oe</filename> uses
288 <filename>.bbappend</filename> files to modify the 291 append files to modify the
289 <filename>QT_SQL_DRIVER_FLAGS</filename> variable to 292 <filename>QT_SQL_DRIVER_FLAGS</filename> variable to
290 enable the appropriate plug-ins. 293 enable the appropriate plug-ins.
291 This variable was added to the <filename>qt4.inc</filename> 294 This variable was added to the <filename>qt4.inc</filename>
@@ -392,7 +395,7 @@
392 as shown above, put it in 395 as shown above, put it in
393 <filename>meta-one/recipes-core/base-files/base-files/one/</filename>. 396 <filename>meta-one/recipes-core/base-files/base-files/one/</filename>.
394 Not only does this make sure the file is used 397 Not only does this make sure the file is used
395 only when building for machine "one" but the 398 only when building for machine "one", but the
396 build process locates the file more quickly.</para> 399 build process locates the file more quickly.</para>
397 <para>In summary, you need to place all files 400 <para>In summary, you need to place all files
398 referenced from <filename>SRC_URI</filename> 401 referenced from <filename>SRC_URI</filename>
@@ -526,12 +529,12 @@
526 "meta" layer at 529 "meta" layer at
527 <filename>meta/recipes-bsp/formfactor</filename>: 530 <filename>meta/recipes-bsp/formfactor</filename>:
528 <literallayout class='monospaced'> 531 <literallayout class='monospaced'>
529 DESCRIPTION = "Device formfactor information" 532 SUMMARY = "Device formfactor information"
530 SECTION = "base" 533 SECTION = "base"
531 LICENSE = "MIT" 534 LICENSE = "MIT"
532 LIC_FILES_CHKSUM = "file://${COREBASE}/LICENSE;md5=4d92cd373abda3937c2bc47fbc49d690 \ 535 LIC_FILES_CHKSUM = "file://${COREBASE}/LICENSE;md5=4d92cd373abda3937c2bc47fbc49d690 \
533 file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420" 536 file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
534 PR = "r41" 537 PR = "r44"
535 538
536 SRC_URI = "file://config file://machconfig" 539 SRC_URI = "file://config file://machconfig"
537 S = "${WORKDIR}" 540 S = "${WORKDIR}"
@@ -540,12 +543,12 @@
540 INHIBIT_DEFAULT_DEPS = "1" 543 INHIBIT_DEFAULT_DEPS = "1"
541 544
542 do_install() { 545 do_install() {
543 # Only install file if it has a contents 546 # Only install file if it has a contents
544 install -d ${D}${sysconfdir}/formfactor/ 547 install -d ${D}${sysconfdir}/formfactor/
545 install -m 0644 ${S}/config ${D}${sysconfdir}/formfactor/ 548 install -m 0644 ${S}/config ${D}${sysconfdir}/formfactor/
546 if [ -s "${S}/machconfig" ]; then 549 if [ -s "${S}/machconfig" ]; then
547 install -m 0644 ${S}/machconfig ${D}${sysconfdir}/formfactor/ 550 install -m 0644 ${S}/machconfig ${D}${sysconfdir}/formfactor/
548 fi 551 fi
549 } 552 }
550 </literallayout> 553 </literallayout>
551 In the main recipe, note the 554 In the main recipe, note the
@@ -596,16 +599,22 @@
596 <filename>THISDIR</filename>. 599 <filename>THISDIR</filename>.
597 The trailing colon character is important as it ensures that 600 The trailing colon character is important as it ensures that
598 items in the list remain colon-separated. 601 items in the list remain colon-separated.
599 <note><para>BitBake automatically defines the 602 <note>
600 <filename>THISDIR</filename> variable. 603 <para>
601 You should never set this variable yourself. 604 BitBake automatically defines the
602 Using <filename>_prepend</filename> ensures your path will 605 <filename>THISDIR</filename> variable.
603 be searched prior to other paths in the final list.</para> 606 You should never set this variable yourself.
604 <para>Also, not all append files add extra files. 607 Using "_prepend" ensures your path will
605 Many append files simply exist to add build options 608 be searched prior to other paths in the final list.
606 (e.g. <filename>systemd</filename>). 609 </para>
607 For these cases, it is not necessary to use the 610
608 "_prepend" part of the statement.</para> 611 <para>
612 Also, not all append files add extra files.
613 Many append files simply exist to add build options
614 (e.g. <filename>systemd</filename>).
615 For these cases, it is not necessary to use the
616 "_prepend" part of the statement.
617 </para>
609 </note> 618 </note>
610 </para> 619 </para>
611 </section> 620 </section>