unix::WindowExt no longer returns pointers for things that aren't act…

…ually pointers

Fixes #256

`get_xlib_window` and `get_xlib_screen_id` previously returned `Option<*mut c_void>` by
casting integer IDs into pointers, which while producing no functionality issues, is
semantically incorrect and rather surprising. Worse still, the docs for `get_xlib_window`
stated that it was in fact a valid pointer.

This is a breaking change, and will require some trivial changes to glutin.

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 - Add support for `Touch` for emscripten backend.
 - Added support for `DroppedFile`, `HoveredFile`, and `HoveredFileCancelled` to X11 backend.
+- **Breaking:** `unix::WindowExt` no longer returns pointers for things that aren't actually pointers; `get_xlib_window` now returns `Option<libc::c_ulong>` and `get_xlib_screen_id` returns `Option<libc::c_int>`.
 
 # Version 0.9.0 (2017-12-01)
 

src/os/unix.rs

@@ -78,12 +78,10 @@ impl EventsLoopExt for EventsLoop {
 
 /// Additional methods on `Window` that are specific to Unix.
 pub trait WindowExt {
-    /// Returns a pointer to the `Window` object of xlib that is used by this window.
+    /// Returns the ID of the `Window` xlib object that is used by this window.
     ///
     /// Returns `None` if the window doesn't use xlib (if it uses wayland for example).
-    ///
-    /// The pointer will become invalid when the glutin `Window` is destroyed.
-    fn get_xlib_window(&self) -> Option<*mut libc::c_void>;
+    fn get_xlib_window(&self) -> Option<libc::c_ulong>;
 
     /// Returns a pointer to the `Display` object of xlib that is used by this window.
     ///
@@ -92,12 +90,12 @@ pub trait WindowExt {
     /// The pointer will become invalid when the glutin `Window` is destroyed.
     fn get_xlib_display(&self) -> Option<*mut libc::c_void>;
 
-    fn get_xlib_screen_id(&self) -> Option<*mut libc::c_void>;
+    fn get_xlib_screen_id(&self) -> Option<libc::c_int>;
 
     fn get_xlib_xconnection(&self) -> Option<Arc<XConnection>>;
 
     fn send_xim_spot(&self, x: i16, y: i16);
-    
+
     /// This function returns the underlying `xcb_connection_t` of an xlib `Display`.
     ///
     /// Returns `None` if the window doesn't use xlib (if it uses wayland for example).
@@ -131,7 +129,7 @@ pub trait WindowExt {
 
 impl WindowExt for Window {
     #[inline]
-    fn get_xlib_window(&self) -> Option<*mut libc::c_void> {
+    fn get_xlib_window(&self) -> Option<libc::c_ulong> {
         match self.window {
             LinuxWindow::X(ref w) => Some(w.get_xlib_window()),
             _ => None
@@ -146,7 +144,7 @@ impl WindowExt for Window {
         }
     }
 
-    fn get_xlib_screen_id(&self) -> Option<*mut libc::c_void> {
+    fn get_xlib_screen_id(&self) -> Option<libc::c_int> {
         match self.window {
             LinuxWindow::X(ref w) => Some(w.get_xlib_screen_id()),
             _ => None

src/platform/linux/x11/window.rs

@@ -519,8 +519,8 @@ impl Window2 {
     }
 
     #[inline]
-    pub fn get_xlib_screen_id(&self) -> *mut libc::c_void {
-        self.x.screen_id as *mut libc::c_void
+    pub fn get_xlib_screen_id(&self) -> libc::c_int {
+        self.x.screen_id
     }
 
     #[inline]
@@ -534,8 +534,8 @@ impl Window2 {
     }
 
     #[inline]
-    pub fn get_xlib_window(&self) -> *mut libc::c_void {
-        self.x.window as *mut libc::c_void
+    pub fn get_xlib_window(&self) -> libc::c_ulong {
+        self.x.window
     }
 
     #[inline]