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| author |   Scott Rifenbark <srifenbark@gmail.com> | 2016-09-01 14:01:21 -0700 |
|---|---|---|
| committer |   Richard Purdie <richard.purdie@linuxfoundation.org> | 2016-09-02 16:29:30 +0100 |
| commit | b543458dd67d24a228fa2db0ecb4ddd20016a560 (patch) | |
| tree | 29024004ea406002f7b92debae767605ef4a6e38 /doc/bitbake-user-manual | |
| parent | 7dff6762148bc2ac8f81d89bbe595dfbfdf7b119 (diff) | |
| download | bitbake-b543458dd67d24a228fa2db0ecb4ddd20016a560.tar.gz | |
bitbake-user-manual: Added "Exporting Variables to the Environment"
Fixes [YOCTO #10196]
Added a new section named "Exporting Variables to the Environment".
This section provides a dedicated description for how to export
variables to the shell.
Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Diffstat (limited to 'doc/bitbake-user-manual')
| -rw-r--r-- | doc/bitbake-user-manual/bitbake-user-manual-metadata.xml | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml b/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml index 64f08157f..d4f73ae14 100644 --- a/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml +++ b/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml @@ -476,6 +476,53 @@ </section> </section> + <section id='exporting-variables-to-the-environment'> + <title>Exporting Variables to the Environment</title> + + <para> + You can export variables to the environment of running + tasks by using the <filename>export</filename> keyword. + For example, in the following example, the + <filename>do_foo</filename> task prints "value from + the environment" when run: + <literallayout class='monospaced'> + export ENV_VARIABLE + ENV_VARIABLE = "value from the environment" + + do_foo() { + bbplain "$ENV_VARIABLE" + } + </literallayout> + <note> + BitBake does not expand <filename>$ENV_VARIABLE</filename> + in this case because it lacks the obligatory + <filename>{}</filename>. + Rather, <filename>$ENV_VARIABLE</filename> is expanded + by the shell. + </note> + It does not matter whether + <filename>export ENV_VARIABLE</filename> appears before or + after assignments to <filename>ENV_VARIABLE</filename>. + </para> + + <para> + It is also possible to combine <filename>export</filename> + with setting a value for the variable. + Here is an example: + <literallayout class='monospaced'> + export ENV_VARIABLE = "<replaceable>variable-value</replaceable>" + </literallayout> + In the output of <filename>bitbake -e</filename>, variables + that are exported to the environment are preceded by "export". + </para> + + <para> + Among the variables commonly exported to the environment + are <filename>CC</filename> and <filename>CFLAGS</filename>, + which are picked up by many build systems. + </para> + </section> + <section id='conditional-syntax-overrides'> <title>Conditional Syntax (Overrides)</title> |