2015-09-22 09:56, Panu Matilainen: > On 09/18/2015 11:33 PM, Mario Carrillo wrote: > > +MOD_DIR := $(DESTDIR)/lib/modules > > +KERNEL_DIR := $(shell uname -r)/extra > > Please don't assume one is always building for the running kernel. > Defaulting around uname -r is perfectly reasonable, but there needs to > be a way to override it from the cli. For example rte.vars.mk has this: > > # can be overriden by make command line or exported environment variable > RTE_KERNELDIR ?= /lib/modules/$(shell uname -r)/build
For info, the ?= operator is a way to give a default value after having included other makefiles which may set a different value. Both ?= and := (or simply =) are overriden by the command line. Only "override VAR =" will not be overriden by the command line.
