Added window parameter to glfwSwapBuffers.
diff --git a/tests/sharing.c b/tests/sharing.c
index 5a2e028..8031a9b 100644
--- a/tests/sharing.c
+++ b/tests/sharing.c
@@ -172,11 +172,12 @@
     {
         glfwMakeContextCurrent(windows[0]);
         draw_quad(texture);
-        glfwSwapBuffers();
 
         glfwMakeContextCurrent(windows[1]);
         draw_quad(texture);
-        glfwSwapBuffers();
+
+        glfwSwapBuffers(windows[0]);
+        glfwSwapBuffers(windows[1]);
 
         glfwWaitEvents();
     }