[dgram] Clarify description of an address which should be used in bind().
Also, tested wildcard addresses to work for bind, so included in the
docs too.
Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
diff --git a/docs/dgram.md b/docs/dgram.md
index 7a931e9..bfe2127 100644
--- a/docs/dgram.md
+++ b/docs/dgram.md
@@ -75,9 +75,13 @@
Bind socket to a local address and port. This is required operation for
server-side sockets, i.e. sockets which wait and receive data from other
-network nodes. `ip_addr` must be a string representing an IP address.
-This module does not support domain name resolution, so only IP addresses
-are allowed. An example of IPv4 address: `'192.0.2.1'`, IPV6: `'2001:db8::1'`.
+network nodes. `ip_addr` must be a string representing an IP address of
+a *local* network interface, or a "wildcard" address of `'0.0.0.0'` (IPv4)
+or `'::'` (IPv6), in which case a socket will be bound to all local
+interfaces. This module does not support domain name resolution, so only
+IP addresses are allowed. At the time of writing, local interface
+addresses are hardcoded to be: `'192.0.2.1'` (IPv4) and `'2001:db8::1'`
+(IPv6) (but these will become configurable in the future).
### DgramSocket.send