I am trying to send data continuously from a c++ code to a python code. I used udp sockets to send the data. The rate of sending is at a faster rate than the receiving rate as it is a simple sensor code. So the data sent is accumulated in the socket. When I try to read the data it returns an old data. How can I read the newest data from the socket or delete the old data when the new data is sent?
How can I read the newest data from the socket or delete the old data when the new data is sent?
Read a packet of data from the socket and place it into a buffer. Keep reading packets from the socket, placing each packet into the buffer each time (replacing whatever packet-data was in the buffer previously), until there is no more data left to read -- non-blocking-I/O mode is useful for this, as a non-blocking recv() will throw a socket.error exception with code EWOULDBLOCK when you've run out of data in the socket's incoming-data-buffer. Once you've read all the data, whatever is left in your buffer is the newest data, so go ahead and use that data.
Sketch/example code follows (untested, may contain errors):
sock = socket.socket(family, socket.SOCK_DGRAM)
[... bind socket, etc... ]
# Receive-UDP-data event-loop begins here
sock.setblocking(False)
while True:
newestData = None
keepReceiving = True
while keepReceiving:
try:
data, fromAddr = sock.recvfrom(2048)
if data:
newestData = data
except socket.error as why:
if why.args[0] == EWOULDBLOCK:
keepReceiving = False
else:
raise why
if (newestData):
# code to handle/parse (newestData) here