diff options
Diffstat (limited to 'build/target')
| -rw-r--r-- | build/target | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/build/target b/build/target index f9aa50a..3d395d4 100644 --- a/build/target +++ b/build/target @@ -30,13 +30,13 @@ namespace build // Target state. // - enum class target_state {unknown, unchanged, changed, failed}; + enum class target_state {unknown, postponed, unchanged, changed, failed}; // Recipe. // - // The returned target state should be either changed or unchanged. - // If there is an error, then the recipe should throw rather than - // returning failed. + // The returned target state should be changed, unchanged, or + // postponed. If there is an error, then the recipe should throw + // rather than returning failed. // // The recipe execution protocol is as follows: before executing // the recipe, the caller sets the target's state to failed. If @@ -44,10 +44,13 @@ namespace build // failed, then the caller sets it to the returned value. This // means that the recipe can set the target's state manually to // some other value. For example, setting it to unknown will - // result in the recipe to be executed again if this target is - // a prerequisite of another target. Note that in this case the + // result in the recipe to be executed again if this target is a + // prerequisite of another target. Note that in this case the // returned by the recipe value is still used (by the caller) as // the resulting target state for this execution of the recipe. + // Returning postponed from the last call to the recipe means + // that the action could not be executed at this time (see fsdir + // clean for an example). // using recipe_function = target_state (action, target&); using recipe = std::function<recipe_function>; @@ -107,7 +110,7 @@ namespace build // action. It is incremented during the match phase and then decremented // during execution, before running the recipe. As a result, the recipe // can detect the last chance (i.e., last dependent) to execute the - // command ("front-running" vs "back-running" recipes). + // command (see alsoe first/last execution modes in <operation>). // // Note that setting a new recipe (which happens when we match the rule // and which in turn is triggered by the first dependent) clears this |