🔗UDP

net/udp.nim provides non-blocking UDP sockets in two modes: bound(server-style, receives from anyone) and connected (client-style, scoped to one peer).

Runnable example: examples/udp_echo.nim.

🔗Bound UDP socket (server)

let sock = bindUdp(loop, "0.0.0.0", 9011,
  proc(sender: Sockaddr_storage; data: openArray[byte]) =
    sock.sendTo(data, sender)     # echo back to the sender
)

The callback receives the sender's address and the datagram bytes. OnUdpData = proc(sender: Sockaddr_storage; data: openArray[byte]) {.closure.}

🔗Connected UDP socket (client)

let sock = connectUdp(loop, "127.0.0.1", 9011, onData)
sock.send("ping")

A connected UDP socket can send (no address) and only receives datagrams from its peer.

🔗Sending

sock.sendTo(data, "example.com", 1234)    # resolve each call (address form)
sock.sendTo(data, addrBuf)                # use a cached Sockaddr_storage
sock.send(data)                           # connected sockets only

The address forms re-resolve per datagram (see async DNS for the run-time resolver); sockaddrFromIp from sockets is the cheap way to build a fixed destination.

🔗Closing

sock.close()

🔗API reference

Full signatures: UDP API. Related: sockets, TCP.