Example "test" segfaults after start

[dpwiz]

In 1d6b7cc97be6973d46aac84f74a881549f39d9cc

[jpwidera]

I'm not sure, but maybe this is somehow related to a missing default value.

setNextWindowPos is calling Raw.setNextWindowPos posPtr cond nullPtr and this itself is calling SetNextWindowPos(const ImVec2& pos, ImGuiCond cond = 0, const ImVec2& pivot = ImVec2(0, 0));. There the nullptr is not replaced by the default argument.

I guess, in the Raw.setNextWindowPos:

setNextWindowPos :: (MonadIO m) => Ptr ImVec2 -> ImGuiCond -> Ptr ImVec2 -> m ()
setNextWindowPos posPtr cond pivotPtr = liftIO do
  [C.exp| void { SetNextWindowPos(*$(ImVec2* posPtr), $(ImGuiCond cond), *$(ImVec2* pivotPtr)) } |]

The transformation from nullPtr to $(ImVec2 pivotPtr)) casts the void to a ImVec2 and therefore is creating a non-valid memory position. But I'm not sure how it is working exactly.

[jpwidera]

A quick Maybe fix can solve this problem:

setNextWindowPos :: (MonadIO m) => Ptr ImVec2 -> ImGuiCond -> Maybe (Ptr ImVec2) -> m ()
setNextWindowPos posPtr cond Nothing = liftIO do
  [C.exp| void { SetNextWindowPos(*$(ImVec2* posPtr), $(ImGuiCond cond)) } |]
setNextWindowPos posPtr cond (Just pivotPtr) = liftIO do
  [C.exp| void { SetNextWindowPos(*$(ImVec2* posPtr), $(ImGuiCond cond), *$(ImVec2* pivotPtr)) } |]

And the call from setNextWindowPos becomes:

      Just pivotRef -> do
        pivot <- get pivotRef
        with pivot $ \pivotPtr ->
          Raw.setNextWindowPos posPtr cond (Just pivotPtr)
      Nothing -> do
        Raw.setNextWindowPos posPtr cond Nothing

[dpwiz]

So, default value is not null, but a static pointer :thinking: Good catch!

[dpwiz]

It works now!