SDL_ShowSimpleMessageBox() are not working on the 64-bit beta-test version of Raspberry Pi OS. This is using SDL 2.0.9, which is the latest version available from the Raspberry Pi repository.
Specifically, the functions immediately return -1, without displaying anything, and
SDL_GetError() reports “No message system available”. This is unexpected because the functions work correctly in mainstream 32-bits Pi OS (‘Raspbian Buster’).
Can anybody shed some light on this? Is the problem likely to be in SDL or at the Raspberry Pi end? It’s important that it be fixed before the 64-bit Pi OS is formally released.