diff options
Diffstat (limited to 'poky/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml')
| -rw-r--r-- | poky/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/poky/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml b/poky/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml index 421364c2c..95a8b95b1 100644 --- a/poky/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml +++ b/poky/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml @@ -5,7 +5,7 @@ <title>Syntax and Operators</title> <para> - Bitbake files have their own syntax. + BitBake files have their own syntax. The syntax has similarities to several other languages but also has some unique features. This section describes the available syntax and operators @@ -294,17 +294,20 @@ rather than when the variable is actually used: <literallayout class='monospaced'> T = "123" - A := "${B} ${A} test ${T}" + A := "test ${T}" T = "456" - B = "${T} bval" + B := "${T} ${C}" C = "cval" C := "${C}append" </literallayout> In this example, <filename>A</filename> contains - "test 123" because <filename>${B}</filename> and - <filename>${A}</filename> at the time of parsing are undefined, - which leaves "test 123". - And, the variable <filename>C</filename> + "test 123", even though the final value of <filename>T</filename> + is "456". + The variable <filename>B</filename> will end up containing "456 cvalappend". + This is because references to undefined variables are preserved as is + during (immediate)expansion. This is in contrast to GNU Make, where undefined + variables expand to nothing. + The variable <filename>C</filename> contains "cvalappend" since <filename>${C}</filename> immediately expands to "cval". </para> @@ -1414,7 +1417,7 @@ </section> <section id='bitbake-style-python-functions-versus-python-functions'> - <title>Bitbake-Style Python Functions Versus Python Functions</title> + <title>BitBake-Style Python Functions Versus Python Functions</title> <para> Following are some important differences between @@ -1864,7 +1867,7 @@ accessing your <filename>$HOME/.ccache</filename> directory. The following command "whitelists" the environment variable - <filename>CCACHE_DIR</filename> causing BitBack to allow that + <filename>CCACHE_DIR</filename> causing BitBake to allow that variable into the datastore: <literallayout class='monospaced'> export BB_ENV_EXTRAWHITE="$BB_ENV_EXTRAWHITE CCACHE_DIR" @@ -1895,7 +1898,7 @@ <para> Sometimes, it is useful to be able to obtain information from the original execution environment. - Bitbake saves a copy of the original environment into + BitBake saves a copy of the original environment into a special variable named <link linkend='var-bb-BB_ORIGENV'><filename>BB_ORIGENV</filename></link>. </para> @@ -2523,6 +2526,9 @@ In the previous example, the <filename>do_packagedata</filename> task of each item in <filename>RDEPENDS</filename> must have completed before <filename>do_package_qa</filename> can execute. + Although <filename>RDEPENDS</filename> contains entries from the + runtime dependency namespace, BitBake knows how to map them back + to the build-time dependency namespace, in which the tasks are defined. </para> </section> @@ -2616,7 +2622,7 @@ <para> It is often necessary to access variables in the BitBake datastore using Python functions. - The Bitbake datastore has an API that allows you this + The BitBake datastore has an API that allows you this access. Here is a list of available operations: </para> |