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Diffstat (limited to 'Documentation/kbuild/kconfig-language.txt')
| -rw-r--r-- | Documentation/kbuild/kconfig-language.txt | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt index b507d61fd41..44e2649fbb2 100644 --- a/Documentation/kbuild/kconfig-language.txt +++ b/Documentation/kbuild/kconfig-language.txt @@ -113,6 +113,13 @@ applicable everywhere (see syntax). That will limit the usefulness but on the other hand avoid the illegal configurations all over. +- limiting menu display: "visible if" <expr> + This attribute is only applicable to menu blocks, if the condition is + false, the menu block is not displayed to the user (the symbols + contained there can still be selected by other symbols, though). It is + similar to a conditional "prompt" attribude for individual menu + entries. Default value of "visible" is true. + - numerical ranges: "range" <symbol> <symbol> ["if" <expr>] This allows to limit the range of possible input values for int and hex symbols. The user can only input a value which is larger than @@ -303,7 +310,8 @@ menu: "endmenu" This defines a menu block, see "Menu structure" above for more -information. The only possible options are dependencies. +information. The only possible options are dependencies and "visible" +attributes. if: @@ -381,3 +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. |