There's gotta be some way to programmatically determine it, right? It may not be portable. It may require some system calls or something, but there's gotta be a way, right?
Maybe a system call that checks whether writing to a page would result in a fault? What if we had memory file descriptors for pages? We'd be able to use them with epoll and io_uring to asynchronously check whether it's safe to write to the pages they represent.
I'm not an expert enough to tell you; I just read the article and decided that it was too long so summarized for others. There's some discussion upthread about catching SIGSEGV and other methods, FWIW.
