From 760b5fafedafbece5386b173fd6ed608fe18af32 Mon Sep 17 00:00:00 2001
From: "matthias.ringwald"
 <matthias.ringwald@1a0a8af8-31b5-11de-8e0c-53a27eea117e>
Date: Sun, 8 Jun 2014 20:25:27 +0000
Subject: [PATCH] check att_write_callback != null before calling it

---
 ble/att.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ble/att.c b/ble/att.c
index eeb59a515..1bf97853a 100644
--- a/ble/att.c
+++ b/ble/att.c
@@ -926,6 +926,7 @@ static uint16_t handle_prepare_write_request(att_connection_t * att_connection,
  * @brief transcation queue of prepared writes, e.g., after disconnect
  */
 void att_clear_transaction_queue(){
+    if (!att_clear_transaction_queue) return;
     (*att_write_callback)(0, ATT_TRANSACTION_MODE_CANCEL, 0, NULL, 0, NULL);
 }