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 | 65 |
1 files changed, 62 insertions, 3 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 b4fc64e75..2490f6e4b 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 @@ -342,7 +342,7 @@ <para> When you use this syntax, BitBake expects one or more strings. - Surrounding spaces are removed as well. + Surrounding spaces and spacing are preserved. Here is an example: <literallayout class='monospaced'> FOO = "123 456 789 123456 123 456 123 456" @@ -352,8 +352,9 @@ FOO2_remove = "abc def" </literallayout> The variable <filename>FOO</filename> becomes - "789 123456" and <filename>FOO2</filename> becomes - "ghi abcdef". + " 789 123456 " + and <filename>FOO2</filename> becomes + " ghi abcdef ". </para> <para> @@ -1929,6 +1930,38 @@ not careful. </note> </para></listitem> + <listitem><para><emphasis><filename>[number_threads]</filename>:</emphasis> + Limits tasks to a specific number of simultaneous threads + during execution. + This varflag is useful when your build host has a large number + of cores but certain tasks need to be rate-limited due to various + kinds of resource constraints (e.g. to avoid network throttling). + <filename>number_threads</filename> works similarly to the + <link linkend='var-BB_NUMBER_THREADS'><filename>BB_NUMBER_THREADS</filename></link> + variable but is task-specific.</para> + + <para>Set the value globally. + For example, the following makes sure the + <filename>do_fetch</filename> task uses no more than two + simultaneous execution threads: + <literallayout class='monospaced'> + do_fetch[number_threads] = "2" + </literallayout> + <note><title>Warnings</title> + <itemizedlist> + <listitem><para> + Setting the varflag in individual recipes rather + than globally can result in unpredictable behavior. + </para></listitem> + <listitem><para> + Setting the varflag to a value greater than the + value used in the <filename>BB_NUMBER_THREADS</filename> + variable causes <filename>number_threads</filename> + to have no effect. + </para></listitem> + </itemizedlist> + </note> + </para></listitem> <listitem><para><emphasis><filename>[postfuncs]</filename>:</emphasis> List of functions to call after the completion of the task. </para></listitem> @@ -2719,4 +2752,30 @@ </itemizedlist> </para> </section> + + <section id='wildcard-support-in-variables'> + <title>Wildcard Support in Variables</title> + + <para> + Support for wildcard use in variables varies depending on the + context in which it is used. + For example, some variables and file names allow limited use of + wildcards through the "<filename>%</filename>" and + "<filename>*</filename>" characters. + Other variables or names support Python's + <ulink url='https://docs.python.org/3/library/glob.html'><filename>glob</filename></ulink> + syntax, + <ulink url='https://docs.python.org/3/library/fnmatch.html#module-fnmatch'><filename>fnmatch</filename></ulink> + syntax, or + <ulink url='https://docs.python.org/3/library/re.html#re'><filename>Regular Expression (re)</filename></ulink> + syntax. + </para> + + <para> + For variables that have wildcard suport, the + documentation describes which form of wildcard, its + use, and its limitations. + </para> + </section> + </chapter> |
