Documentation: kbuild: Improve if_changed documentation

- These days if_changed is used with many more commands than ld,
    objcopy, and gzip, hence add an ellipsis,
  - Any target that utilises if_changed must be listed in $(targets),
    so it needs an assignment to "targets", not "target".

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
This commit is contained in:
Geert Uytterhoeven 2014-08-08 17:23:08 +02:00 committed by Michal Marek
parent b22ae40ef2
commit ef80f0a1e0

View file

@ -1092,7 +1092,7 @@ When kbuild executes, the following steps are followed (roughly):
Usage:
target: source(s) FORCE
$(call if_changed,ld/objcopy/gzip)
$(call if_changed,ld/objcopy/gzip/...)
When the rule is evaluated, it is checked to see if any files
need an update, or the command line has changed since the last
@ -1110,7 +1110,7 @@ When kbuild executes, the following steps are followed (roughly):
significant; for instance, the below will fail (note the extra space
after the comma):
target: source(s) FORCE
#WRONG!# $(call if_changed, ld/objcopy/gzip)
#WRONG!# $(call if_changed, ld/objcopy/gzip/...)
ld
Link target. Often, LDFLAGS_$@ is used to set specific options to ld.
@ -1142,7 +1142,7 @@ When kbuild executes, the following steps are followed (roughly):
The ": %: %.o" part of the prerequisite is a shorthand that
free us from listing the setup.o and bootsect.o files.
Note: It is a common mistake to forget the "target :=" assignment,
Note: It is a common mistake to forget the "targets :=" assignment,
resulting in the target file being recompiled for no
obvious reason.