Kevin Bartlett

@Geoffry Akien--I'm not able to duplicate your 2nd error (the one with jtcp_version01), so I'm not sure what to say about that. Your 1st error is really mysterious: a failed jtcp_request_connection() on my machine results in a "connect timed out" error, but the message you get says "Read timed out". I don't know the inner workings of Java well enough to understand why it should be attempting a read operation when you are requesting a connection, so I'm afraid I'm not going to be able to offer you any help here.

@Sally: It may be possible to do what you want to do, but I don't know how. The only workaround I can think of is to simulate a longer timeout by repeatedly calling jtcp with a short timeout in a loop. You could then interrupt the attempt the normal way you interrupt a loop, i.e., using Ctrl-C, deleting a control file, a GUI callback, etc.

Sorry, Gabriel, I don't know how a multicast packet differs from a regular UDP packet. Can't you just receive them with judp() like a regular UDP packet?

thanks very much for sharing this copy.

I want to use port 502 (I can't change this), but your code formally does not allow the user of ports <1025. I have a device which works just fine using tcpip in the instrument toolbox, but I was hoping to get rid of the dependency by using your code.

Naively changing this limit and using 2012bx64 on W7E I get the following:

>> j = jtcp('REQUEST', '10.10.10.4', 502)
Error using jtcp>jtcp_request_connection (line 293)
Java exception occurred:
java.net.SocketTimeoutException: Read timed out

at java.net.SocketInputStream.socketRead0(Native Method)

at java.net.SocketInputStream.read(Unknown Source)

at java.io.ObjectInputStream$PeekInputStream.read(Unknown Source)

at java.io.ObjectInputStream$PeekInputStream.readFully(Unknown
Source)

at
java.io.ObjectInputStream$BlockDataInputStream.readShort(Unknown
Source)

at java.io.ObjectInputStream.readStreamHeader(Unknown Source)

at java.io.ObjectInputStream.<init>(Unknown Source)

Error in jtcp (line 230)
jTcpObj = jtcp_request_connection(host,port,timeout,serialize);

...but using the same approach with jtcp_version01 seems to work initially:

>> j = jtcp_version01('REQUEST', '10.10.10.4', 502)

j =

socket: [1x1 java.net.Socket]
remoteHost: '10.10.10.4'
port: 502
inputStream: [1x1 java.net.SocketInputStream]
dataInputStream: [1x1 java.io.DataInputStream]
outputStream: [1x1 java.net.SocketOutputStream]
dataOutputStream: [0 java.io.DataOutputStream]

...but then sending something gives this error:

jtcp_version01('WRITE', j, int8(c))
Error using jtcp_version01>jtcp_write (line 384)
Java exception occurred:
java.net.SocketException: Software caused connection abort: socket
write error

at java.net.SocketOutputStream.socketWrite0(Native Method)

at java.net.SocketOutputStream.socketWrite(Unknown Source)

at java.net.SocketOutputStream.write(Unknown Source)

at java.io.DataOutputStream.write(Unknown Source)

Error in jtcp_version01 (line 258)
jtcp_write(jTcpObj,mssg);

...although closing the connection seems to work without complaint.