From 98a9c296f6d469a9b6221eb2e29655610b4d7583 Mon Sep 17 00:00:00 2001
From: Tom Cook <tom.cook@dnvgl.com>
Date: Wed, 27 Jan 2016 12:39:43 +0000
Subject: [PATCH] Made use of std::function ESP8266-specific.

---
 src/PubSubClient.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/PubSubClient.h b/src/PubSubClient.h
index d2cc61c..073a759 100755
--- a/src/PubSubClient.h
+++ b/src/PubSubClient.h
@@ -66,7 +66,11 @@
 #define MQTTQOS1        (1 << 1)
 #define MQTTQOS2        (2 << 1)
 
+#ifdef ESP8266
 #define MQTT_CALLBACK_SIGNATURE std::function<void(char*, uint8_t*, uint32_t)> callback
+#else
+#define MQTT_CALLBACK_SIGNATURE void (*callback)(char*, uint8_t*, uint32_t)
+#endif
 
 class PubSubClient {
 private: