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| -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 48a3981c717b..44e2649fbb29 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. |