linux/kconfig.h: create two- and three-argument versions of CONFIG_IS_ENABLED
This adds a bunch of preprocessor magic to extend the capabilities of
CONFIG_IS_ENABLED. The existing semantics of
CONFIG_IS_ENABLED(FOO)
expanding to a 1 or 0 (depending on build context and the defined-ness
or not of the appropriate CONFIG_FOO/CONFIG_SPL_FOO/CONFIG_TPL_FOO)
are of course preserved. With this, one is also allowed a two-argument
form
CONFIG_IS_ENABLED(FOO, (something))
which expands to something precisely when CONFIG_IS_ENABLED(FOO) would
expand to 1, and expands to nothing otherwise. It is, in other words,
completely equivalent to the three lines
#if CONFIG_IS_ENABLED(FOO)
something
#endif
The second argument must be parenthesized in order to allow any
tokens, including a trailing comma, to appear - one use case for this
is precisely to make it a bit more ergonomic to build an array and
only include certain items depending on .config. That should increase
both readability and not least "git grep"ability.
A third variant is also introduced,
CONFIG_IS_ENABLED(FOO, (xxx), (yyy))
which corresponds to
#if CONFIG_IS_ENABLED(FOO)
xxx
#else
yyy
#endif
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
1 file changed