getaddrs provides a safe interface for the system's network interface data.

The `InterfaceAddrs` struct provides access to the system's network interface data. You can either iterate over it or consume it and convert it into an `InterfaceMap` (a `HashMap<String, Vec<InterfaceAddr>>`) for more convenient access by interface name.


## Examples

You can access the basic information of the system in a few lines. The following program prints all the known addresses.

```
use getaddrs::InterfaceAddrs;

let addrs = InterfaceAddrs::query_system()
    .expect("System has no network interfaces.");

for addr in addrs {
    println!("{}: {:?}", addr.name, addr.address);
}
```

The InterfaceFlags struct provides access to info about the state of an interface. This program prints the addresses of only interfaces which are up.

```
use getaddrs::{InterfaceAddrs, if_flags};

let addrs = InterfaceAddrs::query_system()
    .expect("System has no network interfaces.");

for addr in addrs {
    if addr.flags.contains(if_flags::IFF_UP) {
        println!("{}: {:?}", addr.name, addr.address);
    }
}
```

You can convert the InterfaceAddrs struct into a HashMap easily. InterfaceMap is an alias for HashMap<String, Vec<InterfaceAddr>> for easier reference.

```
use getaddrs::{InterfaceAddrs, InterfaceAddr, InterfaceMap};
use std::collections::HashMap;

let interfaces: InterfaceMap = 
    InterfaceAddrs::query_system()
    .expect("System has no network interfaces.")
    .into(); // Convert to a hash map

// Print all the addresses of the loopback interface
if let Some(addrs) = interfaces.get("lo") {
   println!("Loopback addresses:");
   for addr in addrs {
        println!("\t{:?}", addr);
   }
}
```