From c7e391d65c14c484ed4c4b34cad0fa9e3f06aa55 Mon Sep 17 00:00:00 2001
From: Harry Jeffery <harry@exec64.co.uk>
Date: Thu, 15 Aug 2019 18:49:54 +0100
Subject: wl/x11: Ensure event writes are always atomic

---
 src/wl_window.c  | 6 +++++-
 src/x11_window.c | 4 ++++
 2 files changed, 9 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/wl_window.c b/src/wl_window.c
index b5aac22..021d9aa 100644
--- a/src/wl_window.c
+++ b/src/wl_window.c
@@ -4,12 +4,13 @@
 
 #include <assert.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <poll.h>
 #include <pthread.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 #include <sys/mman.h>
+#include <unistd.h>
 
 #include <wayland-client.h>
 #include <wayland-egl.h>
@@ -687,6 +688,9 @@ static void shutdown_wayland(struct imv_window *window)
 
 struct imv_window *imv_window_create(int width, int height, const char *title)
 {
+  /* Ensure event writes will always be atomic */
+  assert(sizeof(struct imv_event) <= PIPE_BUF);
+
   struct imv_window *window = calloc(1, sizeof *window);
   window->scale = 1;
   window->wl_outputs = list_create();
diff --git a/src/x11_window.c b/src/x11_window.c
index 7bf7d2b..1b7f724 100644
--- a/src/x11_window.c
+++ b/src/x11_window.c
@@ -2,6 +2,7 @@
 
 #include <assert.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <poll.h>
 #include <stdlib.h>
 #include <string.h>
@@ -44,6 +45,9 @@ static void set_nonblocking(int fd)
 
 struct imv_window *imv_window_create(int w, int h, const char *title)
 {
+  /* Ensure event writes will always be atomic */
+  assert(sizeof(struct imv_event) <= PIPE_BUF);
+
   struct imv_window *window = calloc(1, sizeof *window);
   window->pointer.last.x = -1;
   window->pointer.last.y = -1;
-- 
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