While loop not breaking even though condition is met.
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I have an issue where my while loop continues to run even though my if statement, containing a break, inside the loop is met. I have tested this by displaying strings. It does print 'moving stage' when a push the button as well as 'stop stage' when i push it again. The flags I have defined changes between 1 or 0 depending on a button i push in a GUI. How can I terminate my loop?
function Standa_cmd(Stage_functions_settings)
while 1
pause(1)
disp('moving stage')
flag = Stage_functions_settings.move_x; % This struct field changes value between 1 or 0 depending on the button push in the gui
if(flag == 0)
disp('stop stage')
break
end
end
end
댓글 수: 3
Jiri Hajek
2022년 11월 11일
Hi, what you have described does not prove that the break command does not work, which you seem to suggest. Please put a breakpoint inside the if block and then use the F10 key to see what happens... This way, if you are able to get the process to the breakpoint, you will verify the correct functioning of the break command.
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Bruno Luong
2022년 11월 11일
편집: Bruno Luong
2022년 11월 11일
Just guessing; Might be it breaks but your function is entered again or there are many instances of function in queue, log more
function Standa_cmd(Stage_functions_settings)
disp('Standa_cmd is called')
while 1
pause(1)
disp('moving stage')
flag = Stage_functions_settings.move_x; % This struct field changes value between 1 or 0 depending on the button push in the gui
if(flag == 0)
disp('stop stage')
break
end
end
disp('I''m out of the loop and about to quit the function')
end
댓글 수: 13
Bruno Luong
2022년 11월 17일
편집: Bruno Luong
2022년 11월 17일
General principe : finite state machine
I wouldn't rely at all on push button state to make the state mahine (stage run or stop). I recommed this workflow:
I would create the state machine at the single place (a function to handle it) using for example persistent variable.
A second persistent logical variable called StopRequested.
Inside the while loop of the function calls drawnow then check StopRequested. If it's TRUE breaks the while loop.
Everytime user clicks on the button, the callback does this:
- If (and only if) the current state is stop it invokes Standa_cmd
At the begining of function Standa_cmd, it switch StopRequested to FALSE and toggles the state to run (in this order)
The function setups an onCleanup callback that is triggered only when the function quits. The onCleanup callback function toggles the state to stop
The function runs the while loop
- Otherwise (the current state is run) switch StopRequested to TRUE (to signal the while loop to break), do nothing else.
추가 답변 (1개)
Image Analyst
2022년 11월 11일
I think the pushbutton does not set the flag. I've seen this in GUIDE and this is why I use checkboxes instead of a push button. Then simply check the value of the checkbox inside your while loop.
Nonetheless it is possible to use a push button. See attached little demo.
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