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Read line of ASCII string data from remote host over TCP/IP

Since R2020b



data = readline(t) reads ASCII data until the first occurrence of the terminator from the remote host specified by the TCP/IP client t and returns data as a string without the terminator. If the function is unable to return any data within the period specified by the Timeout property of t, it returns data as a 0-by-0 double []. The function suspends MATLAB® execution until the terminator is reached or a timeout occurs.


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Create a TCP/IP client connection called t, connecting to a TCP/IP echo server with port 4000. To do so, you must have an echotcpip server running on port 4000.

t = tcpclient("localhost",4000)
t = 
  tcpclient with properties:

              Address: 'localhost'
                 Port: 4000
    NumBytesAvailable: 0

  Show all properties, functions

Check the default ASCII terminator.

ans = 

Set the terminator to "CR" and write a string of ASCII data. The writeline function automatically appends the terminator to the data.


Write another string of ASCII data with the terminator automatically appended.


Since the client is connected to an echo server, the data you write to the server is returned to the client. Read a string of ASCII data. The readline function returns data until it reaches a terminator.

ans = 

Read a string of ASCII data again to return the second string that you wrote.

ans = 

Close the echo server and clear the TCP/IP client connection.

clear t

Input Arguments

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TCP/IP client, specified as a tcpclient object.

Example: readline(t) reads ASCII data from the remote host specified by the TCP/IP client t.

Version History

Introduced in R2020b