# MessageBox

The MessageBox structure contains functions and structures to create and operate on message boxes.

    structure MessageBox :
    sig
        type HWND

        val IDABORT : int
        val IDCANCEL : int
        val IDCLOSE : int
        val IDHELP : int
        val IDIGNORE : int
        val IDNO : int
        val IDOK : int
        val IDRETRY : int
        val IDYES : int

        structure MessageBoxStyle :
          sig
            include BIT_FLAGS
            val MB_ABORTRETRYIGNORE : flags
            val MB_APPLMODAL : flags
            val MB_DEFAULT_DESKTOP_ONLY : flags
            val MB_DEFBUTTON1 : flags
            val MB_DEFBUTTON2 : flags
            val MB_DEFBUTTON3 : flags
            val MB_DEFBUTTON4 : flags
            val MB_HELP : flags
            val MB_ICONASTERISK : flags
            val MB_ICONERROR : flags
            val MB_ICONEXCLAMATION : flags
            val MB_ICONHAND : flags
            val MB_ICONINFORMATION : flags
            val MB_ICONQUESTION : flags
            val MB_ICONSTOP : flags
            val MB_ICONWARNING : flags
            val MB_NOFOCUS : flags
            val MB_OK : flags
            val MB_OKCANCEL : flags
            val MB_RETRYCANCEL : flags
            val MB_RIGHT : flags
            val MB_RTLREADING : flags
            val MB_SERVICE_NOTIFICATION : flags
            val MB_SERVICE_NOTIFICATION_NT3X : flags
            val MB_SETFOREGROUND : flags
            val MB_SYSTEMMODAL : flags
            val MB_TASKMODAL : flags
            val MB_TOPMOST : flags
            val MB_USERICON : flags
            val MB_YESNO : flags
            val MB_YESNOCANCEL : flags
          end

        val MessageBox : HWND option * string * string * MessageBoxStyle.flags -> int
        val MessageBeep: MessageBoxStyle.flags -> unit

    end