Multiple instances of INADDR_NONE

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Sketch with two files, each importing (directly or indirectly) IPAddress.h
2. avr-nm -n on the resulting elf (on Windows)

What is the expected output? What do you see instead?
Expect only a single instance of INADDR_NONE in .bss section, but multiple are 
allocated, consuming precious SRAM space (in my case of a bigger piece of 
software, seven instances).

Note also that IPAddress consumes six bytes, not four, due to the class pointer 
required for the virtual function.

This is on arduino-1.0.1 under Windows 7.

Please provide any additional information below.
Suggest to declare INADDR_NONE extern in IPAddress.h, and to define it in 
IPAddress.cpp.

Original issue reported on code.google.com by sebastia...@googlemail.com on 16 Aug 2012 at 6:20

[GoogleCodeExporter]

This also occours on arduino 1.0.1 under windows XP, I have a sketch 29Kbyt 
that uses both Ethernet.h and EthernetUdp.h that throws up INADDR_NONE 8 times. 
This uses up a lot of SRAM especially when your trying to improve the sketch so 
it does not crash because variables run into the stack!

Original comment by brucedur...@btinternet.com on 26 Feb 2013 at 8:24

[GoogleCodeExporter]

I believe that I've found another solution to this!! 

INADDR_NONE is only used by Dns.cpp so why is it declared as a const at the end 
if IPAddress.h as though its an afterthought?? 

My solution is to doctor both IPAddress.h (which is in 
x:\..\arduino-1.0.1\hardware\arduino\cores\arduino) to remark out the line 
'const IPAddress INADDR_NONE(0,0,0,0);' and to add this line to the Dns.cpp 
(which is in x:\..\arduino-1.0.1\libraries\Ethernet) just above where it is 
used in 

'// Check we've got a valid DNS server to use
    const IPAddress INADDR_NONE(0,0,0,0);  // These probably a more elegant way to do this but it works
    if (iDNSServer == INADDR_NONE)
    {
        return INVALID_SERVER;
    }'

Which is on lines 129-131.

This gives me back 48bytes of SRAM and incidentally makes the Sketch 200 odd 
bytes smaller!

Original comment by brucedur...@btinternet.com on 7 Mar 2013 at 4:56

[GoogleCodeExporter]

It does of course not matter whereto you more the definition, but if the 
declaration is in IPAddress.h then one would normally expect the definition in 
IPAddress.cpp.

Original comment by sebastia...@googlemail.com on 9 Mar 2013 at 8:22