Wifi.begin() Returns (WiFi101 Library)

There are more returns than described in the Wifi101 Lib Reference:

(Arduino - WiFi101Begin)

You should complete the description with:

Wifi status codes
WL_NO_SSID_AVAIL (1) : assigned when no SSID are available;
WL_SCAN_COMPLETED (2) : assigned when the scan networks is completed;
WL_CONNECTED (3) : assigned when connected to a WiFi network;
WL_CONNECT_FAILED (4) : assigned when the connection fails for all the attempts;
WL_CONNECTION_LOST (5) : assigned when the connection is lost;
WL_DISCONNECTED (6) : assigned when disconnected from a network;