From bc1127da5bb8b1c88e6430e7babb19a4e6d9934b Mon Sep 17 00:00:00 2001
From: Jan Haller <bromeon@gmail.com>
Date: Sun, 27 Apr 2014 12:07:54 +0200
Subject: [PATCH] Output error message and abort program when XOpenDisplay()
 fails

Fixes issue #508.

When the X11 display could not be opened, the application crashed without notice. Now, a meaningful error message is output to std::err() and std::abort() is called, causing immediate program termination.
---
 src/SFML/Window/Unix/Display.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/SFML/Window/Unix/Display.cpp b/src/SFML/Window/Unix/Display.cpp
index 0a35ee4d..aad1b267 100644
--- a/src/SFML/Window/Unix/Display.cpp
+++ b/src/SFML/Window/Unix/Display.cpp
@@ -25,8 +25,10 @@
 ////////////////////////////////////////////////////////////
 // Headers
 ////////////////////////////////////////////////////////////
+#include <SFML/System/Err.hpp>
 #include <SFML/Window/Unix/Display.hpp>
 #include <cassert>
+#include <cstdlib>
 
 
 namespace
@@ -44,7 +46,18 @@ namespace priv
 Display* OpenDisplay()
 {
     if (referenceCount == 0)
+    {
         sharedDisplay = XOpenDisplay(NULL);
+
+        // Opening display failed: The best we can do at the moment is to output a meaningful error message
+        // and cause an abnormal program termination
+        if (!sharedDisplay)
+        {
+            err() << "Failed to open X11 display; make sure the DISPLAY environment variable is set correctly" << std::endl;
+            std::abort();
+        }
+    }
+
     referenceCount++;
     return sharedDisplay;
 }