A Cfunction to get the ip address where the executable is running. 113

Right. Almost every Unix machine with IP networking enabled has a local-loopback interface (on Linux it's 'lo') that's canonically buttigned the IP address 127.0.0.1 ('localhost'). A normal machine also has an Ethernet or similar interface to the LAN, typically the 'eth0' interface, whose address is what most people think of when they think of a machine's IP address. If you've got a VPN set up there'll be a third interface for the local end of the VPN link, and it'll have yet another IP address buttigned by the LAN at the other end of the VPN. So a "normal" single-homed host typically has 2 or 3 IP addresses buttigned to various network interfaces.

Then of course you get into more exotic things like multi-homed machines with multiple network cards (routers are an example), machines with a wireless interface (which is just another network card as far as the system's concerned), machines using the interface alias function to give a single interface more than one IP address... Your typical Windows user doesn't get into that, but even a moderately experienced Unix user may have one or more (I use an alias on eth0 to run a second webserver configured to return 404 Not Found for everything to act as a target for ad server domains, for example).

Basically, in IP networking IP addresses belong to interfaces, not machines. If you're asking what a machine's IP address is, you probably need to stop and think about what you're doing that requires you to know the IP address and why you need it. Chances are you've confused something somewhere.

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