Why does MATLAB produce an error when I execute WAITFORBUTTONPRESS and close the figure window without clicking on the figure?

I am using the WAITFORBUTTONPRESS function to block caller input until a mouse click is detected or a key is pressed.

While MATLAB is waiting for a button press, if I close the figure window by clicking on the close icon at the top-right corner of the window, MATLAB throws the following error:

 ??? Error using ==> waitforbuttonpress

 waitforbuttonpress exit because all figures have been deleted

This is not documented in the help page for WAITFORBUTTONPRESS.

Answer 1

[MathWorks Support Team]

This change has been incorporated into the documentation in Release 2009b (R2009b). For previous releases, read below for any additional information:

This is an error in the documentation for MATLAB 7.7 (R2008b) within the WAITFORBUTTONPRESS section. The documentation should read as follows:

You can interrupt WAITFORBUTTONPRESS by typing Ctrl+C, but an error

results unless the function is called from within a try-catch block.

WAITFORBUTTONPRESS also returns an error if you close the

figure by clicking the X(close) button unless you call WAITFORBUTTONPRESS within a try-catch block.