diff options
Diffstat (limited to 'documentation')
-rw-r--r-- | documentation/dev-manual/dev-manual-common-tasks.xml | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/documentation/dev-manual/dev-manual-common-tasks.xml b/documentation/dev-manual/dev-manual-common-tasks.xml index 4a58a6f490..6ae7730f81 100644 --- a/documentation/dev-manual/dev-manual-common-tasks.xml +++ b/documentation/dev-manual/dev-manual-common-tasks.xml | |||
@@ -1400,8 +1400,13 @@ | |||
1400 | <title>Understanding Recipe Syntax</title> | 1400 | <title>Understanding Recipe Syntax</title> |
1401 | 1401 | ||
1402 | <para> | 1402 | <para> |
1403 | The basic items that make up a BitBake recipe file are | 1403 | Understanding recipe file syntax is important for |
1404 | as follows: | 1404 | writing recipes. |
1405 | The following list overviews the basic items that make up a | ||
1406 | BitBake recipe file. | ||
1407 | For more complete BitBake syntax descriptions, see the | ||
1408 | "<ulink url='&YOCTO_DOCS_BB_URL;#bitbake-user-manual-metadata'>Syntax and Operators</ulink>" | ||
1409 | chapter of the BitBake User Manual. | ||
1405 | <itemizedlist> | 1410 | <itemizedlist> |
1406 | <listitem><para><emphasis>Variable Assignments and Manipulations:</emphasis> | 1411 | <listitem><para><emphasis>Variable Assignments and Manipulations:</emphasis> |
1407 | Variable assignments allow a value to be assigned to a | 1412 | Variable assignments allow a value to be assigned to a |
@@ -1519,18 +1524,16 @@ | |||
1519 | <filename>local.conf</filename> file for variables | 1524 | <filename>local.conf</filename> file for variables |
1520 | that are allowed to come through from the external | 1525 | that are allowed to come through from the external |
1521 | environment. | 1526 | environment. |
1522 | Doing so allows you to actually set variables from | 1527 | </para> |
1523 | the external environment that would otherwise be | 1528 | <para>Here is an example where |
1524 | overwritten.</para> | 1529 | <filename>VAR1</filename> is set to "New value" if |
1525 | <para>Here is an example: | 1530 | it is currently empty. |
1531 | However, if <filename>VAR1</filename> has already been | ||
1532 | set, it remains unchanged: | ||
1526 | <literallayout class='monospaced'> | 1533 | <literallayout class='monospaced'> |
1527 | VAR1 ?= "New value" | 1534 | VAR1 ?= "New value" |
1528 | </literallayout> | 1535 | </literallayout> |
1529 | In the previous example, <filename>VAR1</filename> is | 1536 | In this next example, <filename>VAR1</filename> |
1530 | set to "New value" if it is currently empty. | ||
1531 | However, if <filename>VAR1</filename> has already been | ||
1532 | set, it remains unchanged.</para> | ||
1533 | <para>In this next example, <filename>VAR1</filename> | ||
1534 | is left with the value "Original value": | 1537 | is left with the value "Original value": |
1535 | <literallayout class='monospaced'> | 1538 | <literallayout class='monospaced'> |
1536 | VAR1 = "Original value" | 1539 | VAR1 = "Original value" |
@@ -1632,7 +1635,7 @@ | |||
1632 | </literallayout> | 1635 | </literallayout> |
1633 | </para></listitem> | 1636 | </para></listitem> |
1634 | <listitem><para><emphasis>Shell Function Syntax:</emphasis> | 1637 | <listitem><para><emphasis>Shell Function Syntax:</emphasis> |
1635 | Use shell function syntax as if you were writing a shell | 1638 | Write shell functions as if you were writing a shell |
1636 | script when you describe a list of actions to take. | 1639 | script when you describe a list of actions to take. |
1637 | You should ensure that your script works with a generic | 1640 | You should ensure that your script works with a generic |
1638 | <filename>sh</filename> and that it does not require | 1641 | <filename>sh</filename> and that it does not require |