How to define input parameters for BytesAvailableFcn (tcpclient)

Hy all,

my problem concerns the use of input arguments when I define the BytesAvailableFcn of a tcpclient connection.

I create a tcpclient connection:

t = tcpclient('address', port);

And I send a request to the server (which starts automatically to send data):

write( t, 'request' );

I want to have a callback function triggered by a bytes available event:

configureCallback( t, "terminator", @MyCallbackFcn );

MyCallbackFcn is written in a separated MyCallbackFcn.m file. The callback function MyCallbackFcn is triggeredd whenever a terminator is available to be read from the remote host specified by the TCP/IP client.

At the moment, MyCallbackFcn uses global parameters (var1, var2, etc.) defined in the main program:

function MyCallbackFcn( src, ~ )

global var1 var2

...

end

This algorithm works well. But in order to avoid the use of global parameters, I would like to define input parameters for MyCallbackFcn fonction. My problems start here, because I do not find the right form to write:

• the definition of the callback function in the main program : configureCallback( t,...
• the function MyCallbackFcn in the MyCallbackFcn.m file

Thank you in advance for your help.

Raphaël

Answer 1

[Walter Roberson]

https://www.mathworks.com/help/matlab/math/parameterizing-functions.html

[Raphaël Rouveure]

Thanks for your answer Walter.

I read the Matlab documentation about "parameteriring functions" that you have indicated. This topic explains how to store or access extra parameters for mathematical functions that you pass to MATLAB® function functions, such as fzero or integral. But I want to use a function which is not a MATLAB function, so this solution seems to by not adapted to my problem.

[Walter Roberson]

configureCallback(t, @(src,event) MyCallbackFcn(src, event, var1, var2)

function MyCallbackFcn(stc, event, var1, var2)

[Raphaël Rouveure]

Hi Walter,

thanks for the two lines of code, it works fine!

I knew it was possible to use input parameters with the configureCallback function, but I couldn't find the correct syntax...

[Nitin Kumar]

In the syntax correct for the first statement?

[Walter Roberson]

@Nitin Kumar

configureCallback(t, @(src,event) MyCallbackFcn(src, event, var1, var2)

is correct syntax for configuring a callback to MyCallbackFcn passing in two extra parameters, including var1 and var2 . The var1 and var2 values would be "captured" at the time the @(src,event) was processed -- any changes to var1 or var2 made after that point in the code would have no effect on the configured callback.

[Nitin Kumar]

We need to pass the "terminator" argument. Also, a closing parenthesis is missing.

configureCallback(t, "terminator", @(src, event) MyCallbackFcn(src, event, var1, var2))

Just small things but took me some time to figure out. Thanks.