= README Android ifaddrs

Android API level < 24 doesn't provide `getifaddrs` and related functions, we
have tested multiple ways to overcome this issue.


== Non Weorking alternative implementations

https://github.com/kmackay/android-ifaddrs
https://github.com/morristech/android-ifaddrs
https://www.openhub.net/p/android-ifaddrs/

Compiles but then segfault at runtime.


== Qt implementation

Using `QNetworkInterface::allAddresses()` provided by Qt works but at time of
writing (Q4 2021) on newer Android the log is flooded by warnings as we reported
here
https://bugreports.qt.io/browse/QTBUG-78659
plus depending on Qt networking module just for this is frustrating.

Update: the warning flood seems have been fixed in later Qt versions
https://bugreports.qt.io/browse/QTBUG-86394

This solution was the first working we implemented in our code it has been
removed to avoid dependency on Qt, as lighter alternatives are possible.


== Code copied from Android Gingerbread release

As explained here
https://stackoverflow.com/a/57112520

even older Android have `getifaddrs` implementations but doesn't make them
accessible in the API, in particular the one included in Android Gingerbread

https://android.googlesource.com/platform/libcore/+/refs/heads/gingerbread-release/luni/src/main/native/ifaddrs-android.h
https://android.googlesource.com/platform/libcore/+/refs/heads/gingerbread-release/

is particularly easy to include in our code base and compile.

This solution seems the best fitting and doesn't introduce dependency on Qt.
Newer Android releases (expecially 11) have introduced multiple restrictions
on network information access so we suggest you to prepare different APK for
different API level in order to use the `getifaddrs` provided by Android NDK
which deal gracefully with those restrictions as soon as available.