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| author | Randy Dunlap <randy.dunlap@oracle.com> | 2011-04-28 10:58:52 -0700 |
|---|---|---|
| committer | Michal Marek <mmarek@suse.cz> | 2011-05-02 17:39:24 +0200 |
| commit | 64b81ed7fb1e45c914317b20316f32827bc6444b (patch) | |
| tree | 4766f00719fb9cd64c091b8b11cb86d6e7803e7e /Documentation/kbuild | |
| parent | df835c2e7fa875618cc14ced0110ea96f79536fb (diff) | |
kconfig-language: add to hints
Explain a little about kconfig symbol dependencies and symbol
existence given optional kconfig language scenarios.
Yes, I was bitten by this.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Diffstat (limited to 'Documentation/kbuild')
| -rw-r--r-- | Documentation/kbuild/kconfig-language.txt | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt index 48a3981c717..44e2649fbb2 100644 --- a/Documentation/kbuild/kconfig-language.txt +++ b/Documentation/kbuild/kconfig-language.txt @@ -389,3 +389,25 @@ config FOO limits FOO to module (=m) or disabled (=n). +Kconfig symbol existence +~~~~~~~~~~~~~~~~~~~~~~~~ +The following two methods produce the same kconfig symbol dependencies +but differ greatly in kconfig symbol existence (production) in the +generated config file. + +case 1: + +config FOO + tristate "about foo" + depends on BAR + +vs. case 2: + +if BAR +config FOO + tristate "about foo" +endif + +In case 1, the symbol FOO will always exist in the config file (given +no other dependencies). In case 2, the symbol FOO will only exist in +the config file if BAR is enabled. |