added const keyword to Ethernet.hostname() & Dhcp.getHostname()

Author: mykh

src/Dhcp.cpp

@@ -474,7 +474,7 @@ IPAddress DhcpClass::getDnsServerIp()
     return IPAddress(_dhcpDnsServerIp);
 }
 
-char* DhcpClass::getHostname()
+const char* DhcpClass::getHostname() const
 {
     return _dhcpHostname;
 }

src/Dhcp.h

@@ -171,7 +171,7 @@ class DhcpClass {
   IPAddress getGatewayIp();
   IPAddress getDhcpServerIp();
   IPAddress getDnsServerIp();
-  char* getHostname();
+  const char* getHostname() const;
 
   int beginWithDHCP(uint8_t *, unsigned long timeout = 60000, unsigned long responseTimeout = 4000);
   int beginWithDHCP(uint8_t *, const char *, unsigned long timeout = 60000, unsigned long responseTimeout = 4000);

src/Ethernet.cpp

@@ -138,7 +138,7 @@ IPAddress EthernetClass::dnsServerIP()
   return _dnsServerAddress;
 }
 
-char* EthernetClass::hostname()
+const char* EthernetClass::hostname() const
 {
   return _dhcp ? _dhcp->getHostname() : "";
 }

src/Ethernet.h

@@ -32,7 +32,7 @@ class EthernetClass {
   IPAddress subnetMask();
   IPAddress gatewayIP();
   IPAddress dnsServerIP();
-  char* hostname();
+  const char* hostname() const;
 
   friend class EthernetClient;
   friend class EthernetServer;