Define a callback function in a script passing parameters

the question can be more general:

how to hanle a callback function call with @function in a matlab script, also passing parameters. I'm also talking aboutthe syntax (usually i used them in a GUI)

In my specific case:

i'm using a CAN and I want to transmit-receive messages at the same time. I'm trying to use an asyncronus transmission and assign a callback function to handle data when i receive messages. I don't know how handle @receivingFcn since i don't know if i shall define it as a normal function and how to pass parameters

The script is:

% I create a CAN channel

txCh = canChannel('NI','CAN1');

% Create the messages to send using the canMessage function.

msgTx = canMessage(72, false, 6);

% I assign a callback function when i receive a message

txCh.MessageReceivedFcn = @receivingFcn;

txCh.MessageReceivedFcnCount = 30;

% Register each message on the channel at a specified periodic rate.

transmitPeriodic(txCh, msgTx, 'On', 0.01);

the receivingFcn should use the channel and a table, and just contain:

rxMsg = receive(txCh, Inf, 'OutputFormat', 'timetable');

% I save the msg in a txt

rxMsgTable = timetable2table(rxMsg);

tableRx.table2=[tableRx.table2; rxMsgTable];

writetable(rxMsgTable, ['test' char(rxMsg.Time(1)) '.txt'])

Thanks

Answer 1

[Piyush Aggarwal]

Hello Stefano,

I hope the following simple code snipet will clear your doubt on the use of function handles and parameter passing in them.

% Say you have the following simple function to calculate Geometric mean of two vectors x & y
function out = myFunc(x, y)
    out = sqrt(x .* y);
end 

Now you want to create a handle to this function and call it with some parameters inside some .M script

% Inputs or the parameters with which you want to call the function
in1 = [25 18];
in2 = [1 2];
% Create handle to function
fHndl = @myFunc
% Call your function with the inputs
myOut = fHndl(in1, in2);

The Function handle notation is particularly useful when you need to pass functions as an input to another function.

You may refer to the documentaion for more details : https://www.mathworks.com/help/matlab/matlab_prog/creating-a-function-handle.html

If you were looking for "How to pass multiple extra parameters to a function using the @ operator ", refer to this documentation link : https://www.mathworks.com/help/optim/ug/passing-extra-parameters.html