How to add a time limit to response time?

I want to add time limit to the response time. I have a code for "wait for response", but I don't know where and what code I should add. (I refered several codes but didn't work) I'm using Psychtoolbox,

%Wait for response    
    while keyOn == 0
        [keyIsDown,secs,keycode] = KbCheck;
        if keycode(spaceKey) || keycode(num1Key) || keycode(num2Key) || keycode(num3Key) ...
                || keycode(num4Key) || keycode(num5Key) || keycode(num6Key) ...
                    || keycode(num7Key) || keycode(num8Key) || keycode(num9Key)
            keyOn = 1;
        end
    end

Thank you!

[Aquatris]

Can you add tic toc to your code?

You can start a tic and if toc gives you higher than the time limit you break the loop.

Answer 1

[Jeff Miller]

One way is to use GetSecs, which returns the current time. For example,

MaxWait = 1.5;  % As an example, suppose you want a maximum RT of 1.5 seconds
StopTime = GetSecs + MaxWait;  % This computes the time at which you want to stop (max RT)
while (keyOn==0) && (GetSecs<StopTime)  % add the time check to your while loop
    % The rest of your while loop goes here
end
% You will reach this point if a key is pressed or if MaxWait elapses with no key press.

[Takara Sumoto]

Dear Mr. Miller,

Thank you! It worked perfectly.