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| Author | Forum: PowerTCP Telnet for .NET Topic: How to receive more than 2^13 characters |
| mhenne From: Luxembourg Posts: 1 Member Since: 10/16/15 |
posted October 16, 2015 1:55 AM Hi Dart, by doing the following Public Function Telnet_Receive() As String Dim s As String Dim x As Long Sheet1.Telnet1.Receive s Telnet_Receive = s x = Len(s) End Function the maximum length of the received string is always 8192 characters. Is it possible to increase the buffer size of the received string, so that I can receiver more than 8192 characters in one go? If yes, how can I do this? Further on, by doing a workaround with a DO...WHILE loop as shown below, I am receiving more than 2^13 characters, but unfortunately not always. The Telnet ActiveX element receives very often just 3752 characters. The outcome is random, but I can reproduce that behavior. Do response = Telnet_Receive() ans = ans & response Loop While Len(response) = 8192 Public Function Telnet_Receive() As String Dim s As String Dim x As Long Sheet1.Telnet1.timeout = 5000 Sheet1.Telnet1.Receive s Telnet_Receive = s End Function Marc |
Mike Baldwin (Admin) From: Rome, NY USA Posts: 114 Member Since: 04/11/00 Extra Support Options Custom Application Development |
posted October 20, 2015 3:47 PM Hi Marc, The Telnet control queries the socket to see how much data can be read at once, dynamically creates an array of that size, then returns that data into the String parameter you provided. This is controlled by the size of the socket receive window, which defaults to 8K (as you observed). I believe there is a registry entry that can change this default value: [HKEY_LOCAL_MACHINE \SYSTEM \CurrentControlSet \Services \Afd \Parameters] DefaultReceiveWindow = 16384 DefaultSendWindow = 16384 There is also a Telnet.Socket property that can be used for making a WIN32 call to setsockopt() to change the default size. I'd send you a snippet if I had one, but I'm sure there are resources on the web you can find. In general, you never know how much data is available when your code calls Telnet.Receive (because issues like network speeds, equipment, and latency come into play), but it sounds like you're moving a lot of data and I can see why you might want to increase the buffer size. If you get stuck, please call us and we can provide an hour or 2 of consulting to get you on your way. Happy coding, and thanks for using our products. Kind Regards, Mike ------ |
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