diff options
Diffstat (limited to 'libbuild2/config/init.cxx')
| -rw-r--r-- | libbuild2/config/init.cxx | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/libbuild2/config/init.cxx b/libbuild2/config/init.cxx index 1f053e9..c9c6130 100644 --- a/libbuild2/config/init.cxx +++ b/libbuild2/config/init.cxx @@ -56,7 +56,35 @@ namespace build2 // vp.insert<path> ("config.config.save", true /* ovr */); - // @@ TODO + // Configuration variables persistence mode. + // + // By default a config.* variable is saved in the config.build file if + // (1) it is explicitly marked as persistent with save_variable() and + // (2) it is not inherited from an amalgamation that also saves this + // variable (however, there are some exception; see save_config() for + // details). If the first condition is not met, then the variable is + // presumed to be no longer used. + // + // The config.config.persist can be used to adjust this default logic. + // It contains a list of key-value pairs with the key being a variable + // name pattern and the value specifying the condition/action: + // + // <pair> = <pattern>@<condition>=<action> + // <condition> = unused|inherited|inherited-used|inherited-unused + // <action> = (save|drop)[+warn] + // + // The last pattern and condition that matches is used (we may want to + // change this to more specific pattern later). + // + // Note that support for inherited conditions is still a @@ TODO. + // + // The create meta-operation by default (i.e., unless a custom value is + // specified) saves unused config.import.* variables without a warning + // (since there is no way to "use" such variables in a configuration). + // + // Note that variable patterns must be quoted, for example: + // + // b "config.config.persist='config.*'@unused=save+warn" // // Use the NULL value to clear. // |