From 792c251890d67ac643785def4ff5d8ee59318656 Mon Sep 17 00:00:00 2001
From: Xinquan Zhu <xinquanzhu@gmail.com>
Date: Thu, 17 Jul 2014 10:50:43 +0900
Subject: [PATCH] throw an Exception when header is already been sent

---
 lib/Cake/Network/CakeResponse.php | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/lib/Cake/Network/CakeResponse.php b/lib/Cake/Network/CakeResponse.php
index 637299177..b5b0cd881 100644
--- a/lib/Cake/Network/CakeResponse.php
+++ b/lib/Cake/Network/CakeResponse.php
@@ -518,14 +518,16 @@ class CakeResponse {
  * @param string $value the header value
  * @return void
  */
-	protected function _sendHeader($name, $value = null) {
-		if (!headers_sent()) {
+    protected function _sendHeader($name, $value = null) {
+		if (!headers_sent($filename, $linenum)) {
 			if ($value === null) {
 				header($name);
 			} else {
 				header("{$name}: {$value}");
 			}
-		}
+		} else {
+            throw new Exception("Headers already sent in $filename on line $linenum\n");
+        }
 	}
 
 /**