BitBake User Manual - CH3.3. Sharing Functionality

BitBake 有metadata sharing的機制，基本上分為兩類，include file(.inc)跟class file(.bbclass)，你可以使用include或require來include .inc檔案，其行為就是會將.inc內容插入include那行的位置中。
include跟require相似，差異是，如果檔案不存在include不會error，但是requre就會，如：

include foo_no_exist.inc
require foo_need_exist.inc

你可以使用iherit來使用class file，使用這指令會去尋找對應的class來使用，如：

inherit autotools

如果每個recipes都需要inherit的話，可以在.conf使用INHERIT指令達成這目的，如：

INHERIT += sanity

example：meta/conf/sanity.conf

# Sanity checks for common user misconfigurations
#
# See sanity.bbclass
#
# Expert users can confirm their sanity with "touch conf/sanity.conf"
BB_MIN_VERSION = "1.27.1"

SANITY_ABIFILE = "${TMPDIR}/abi_version"

SANITY_VERSION ?= "1"
LOCALCONF_VERSION  ?= "1"
LAYER_CONF_VERSION ?= "6"
SITE_CONF_VERSION  ?= "1"

INHERIT += "sanity"

example：meta/classes/sanity.bbclass

參考資料：
1. BitBake User Manual