using pnet for tcp/ip connection in matlab

I am trying to use pnet to do a client-server opertaion in matlab. I think it should be very simple, but I dont know why I dont seem to be receiving anything on the client side. This is my code, any examples is really appreciated!!

server:

udp1 = pnet('tcpsocket',port1);
pnet(udp1,'setwritetimeout',2);
val  = pnet(udp1,'tcplisten');

if val~=-1,
   while 1
    %get data
    pnet(val,'write',data);
   end
end
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client:
udpB=pnet('tcpconnect','localhost',lport);
pnet(udpB,'setreadtimeout',2);
sockcon=pnet('tcpsocket',lport);

while 
    data_read = pnet(sockcon,'read',100,'double');
end
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the udp1 and udpB values are not -1, so there is a connection.however the data_read value is []. Why????