From fcd220b4fd254f45305fb65512e53d0371dc466c Mon Sep 17 00:00:00 2001 From: Joshua Lock Date: Tue, 8 Jun 2010 17:53:25 +0100 Subject: handbook: document the LAYERDIR variable LAYERDIR is one of the few variables which requires immediate expansion and is worth documenting explicitly. Signed-off-by: Joshua Lock --- handbook/extendpoky.xml | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'handbook/extendpoky.xml') diff --git a/handbook/extendpoky.xml b/handbook/extendpoky.xml index b437c77fa..936a74480 100644 --- a/handbook/extendpoky.xml +++ b/handbook/extendpoky.xml @@ -582,12 +582,17 @@ require conf/distro/include/poky-extras-src-revisions.inc As can be seen, the layers recipes are added to BBFILES. The BBFILE_COLLECTIONS variable is then appended to with the layer name. The BBFILE_PATTERN variable is immediately expanded - with a regular expression used to match files from BBFILES into a - particular layer, in this case by using the base pathname. + with a regular expression used to match files from BBFILES into + a particular layer, in this case by using the base pathname. The BBFILE_PRIORITY variable then assigns different priorities to the files in different layers. This is useful in situations where the same package might appear in multiple layers and allows you to choose which layer should 'win'. + Note the use of LAYERDIR with the immediate expansion operator. + LAYERDIR expands to the directory of the current layer and + requires use of the immediate expansion operator so that Bitbake + does not lazily expand the variable when it's parsing a + different directory. -- cgit v1.2.3