Call XInitThreads once before the first Xlib call. Suggested by Brian Griffin.

2 files changed, 18 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 09f0acd..75a617f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2013-02-18  Jan Nijtmans  <nijtmans@users.sf.net>
+
+	* unix/tkUnixEvent.c: Call XInitThreads once before the
+	first Xlib call. Suggested by Brian Griffin.
+
 2013-01-14  Jan Nijtmans  <nijtmans@users.sf.net>
 
 	* win/tcl.m4: More flexible search for win32 tclConfig.sh,
diff --git a/unix/tkUnixEvent.c b/unix/tkUnixEvent.c
index 4d0ccfa..6268b25 100644
--- a/unix/tkUnixEvent.c
+++ b/unix/tkUnixEvent.c
@@ -116,8 +116,20 @@ TkpOpenDisplay(
     const char *displayNameStr)
 {
     TkDisplay *dispPtr;
-    Display *display = XOpenDisplay(displayNameStr);
+    Display *display;
+#ifdef TCL_THREADS
+    static int xinited = 0;
+
+    if (!xinited) {
+	/* Necessary for threaded apps, of no consequence otherwise  */
+	/* need only be called once, but must be called before *any* */
+	/* Xlib call is made.                                        */
+	XInitThreads();
+	xinited = 1;
+    }
+#endif
 
+    display = XOpenDisplay(displayNameStr);
     if (display == NULL) {
 	return NULL;
     }