udpsocket.recvfrom_nonblock(maxlen, flags) => [mesg, sender_inet_addr]
Receives up to maxlen bytes from udpsocket
using
recvfrom(2) after O_NONBLOCK is set for the underlying file descriptor. If
maxlen is omitted, its default value is 65536. flags is
zero or more of the MSG_
options. The first element of the
results, mesg, is the data received. The second element,
sender_inet_addr, is an array to represent the sender address.
When recvfrom(2) returns 0, Socket#recvfrom_nonblock returns an empty string as data. It means an empty packet.
Parameters
-
maxlen
- the number of bytes to receive from the socket -
flags
- zero or more of theMSG_
options
Example
require 'socket' s1 = UDPSocket.new s1.bind("127.0.0.1", 0) s2 = UDPSocket.new s2.bind("127.0.0.1", 0) s2.connect(*s1.addr.values_at(3,1)) s1.connect(*s2.addr.values_at(3,1)) s1.send "aaa", 0 begin # emulate blocking recvfrom p s2.recvfrom_nonblock(10) #=> ["aaa", ["AF_INET", 33302, "localhost.localdomain", "127.0.0.1"]] rescue IO::WaitReadable IO.select([s2]) retry end
Refer to Socket#recvfrom for the exceptions that may be thrown if the call to recvfrom_nonblock fails.
#recvfrom_nonblock may raise any error corresponding to recvfrom(2) failure, including Errno::EWOULDBLOCK.
If the exception is Errno::EWOULDBLOCK or Errno::AGAIN, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying recvfrom_nonblock.
Please login to continue.