From 5666ec2ec1e026c64cf0bf8b42b1bced4144080b Mon Sep 17 00:00:00 2001
From: Victor Tseng <palatis@gmail.com>
Date: Tue, 13 Sep 2016 00:32:29 +0800
Subject: [PATCH] const-correctness `IPAddress::toString()`

it doesn't modify any member variables, should be safe to be const.
---
 cores/esp8266/IPAddress.cpp | 2 +-
 cores/esp8266/IPAddress.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/cores/esp8266/IPAddress.cpp b/cores/esp8266/IPAddress.cpp
index 93a081eb2..3349c2c5b 100644
--- a/cores/esp8266/IPAddress.cpp
+++ b/cores/esp8266/IPAddress.cpp
@@ -105,7 +105,7 @@ size_t IPAddress::printTo(Print& p) const {
     return n;
 }
 
-String IPAddress::toString()
+String IPAddress::toString() const
 {
     char szRet[16];
     sprintf(szRet,"%u.%u.%u.%u", _address.bytes[0], _address.bytes[1], _address.bytes[2], _address.bytes[3]);
diff --git a/cores/esp8266/IPAddress.h b/cores/esp8266/IPAddress.h
index 9e7dfe5e2..1d0d3acaf 100644
--- a/cores/esp8266/IPAddress.h
+++ b/cores/esp8266/IPAddress.h
@@ -77,7 +77,7 @@ class IPAddress: public Printable {
         IPAddress& operator=(uint32_t address);
 
         virtual size_t printTo(Print& p) const;
-        String toString();
+        String toString() const;
 
         friend class EthernetClass;
         friend class UDP;