MATLAB: Is there an error in the documentation for External Interfaces in MATLAB 7.0 (R14) with how MATLAB handles undefined methods

MATLAB

I have a created a file foo.m on my MATLAB path. The contents of the file are below.

function foo(a)
disp(a)

When I execute the following command

   ja=java.lang.String('aaa');
ja.foo

I receive the following result

 a =
 aaa

The documentation states that MATLAB looks for built-in functions when a MATLAB command invokes a nonexistent method on a Java object.

Best Answer

This change has been incorporated into the documentation in Release 14 Service Pack 3 (R14SP3). For previous releases, read below for any additional information:

This is an error within the documentation for MATLAB within the External Interfaces section. The documentation should read as follows:

If your MATLAB command invokes a nonexistent method on a Java object, MATLAB looks for a function with the same name. If MATLAB finds a function of that name, it attempts to invoke it. If MATLAB does not find a function with that name, it displays a message stating that it cannot find a method by that name for the class.

Related Solutions

MATLAB: Does a figure window open in the foreground in MATLAB 7.0 (R14) when I create the figure using Visual Basic

This change has been incorporated into the documentation in Release 14 Service Pack 3 (R14SP3). For previous releases, read below for any additional information:

This is an error within the documentation for MATLAB 7.0 (R14) within the External Interfaces section . The documentation should read as follows:

Note that in MATLAB 7.0 (R14), figure windows are be generated in the foreground.

MATLAB: Does the Simulink model, which used to work fine in Simulink 4.0 (R12), return an error message “One or more output arguments not assigned during call” when executed in Simulink 6.0 (R14) and later versions

This is expected behavior. This error obtained is due to the change in behavior in the way that output arguments are assigned inside a M-function call.

In the newer release, you need to assign an output inside M-function, if one is requested, or throw an error if no output is available. The older release implicitly assigned [] to the output.

To work around this issue, you can return an empty value to the function output argument, as in the following example:

function y = foo(a)
disp('hello world ');
y=[];

Here is some additional information about the change in functionality:

There is a minor change from MATLAB 6.0 (R12) to MATLAB 7.0 (R14) and later in the way output arguments are assigned during a function call.

Consider the following example:

function y = foo(a)
disp('hello world');

If you execute this function in MATLAB 7.0.4 (R14SP2), you see the following result:

 >> x = foo(2)
 hello world 
 ??? Output argument "y" (and maybe others) not assigned during call to "Y:\1-1UZXOV\foo.m (foo)".
 Error in ==> foo at 2
 disp('hello world ');

If you execute the same function in MATLAB 6.0 (R12), you see the following result:

 >> x = foo(2)
 hello world 
 Warning: One or more output arguments not assigned during call to 'foo'.
 >>

Behavior that resulted in a warning in MATLAB 6.0 (R12) results in an error in MATLAB 7.0 (R14) and later versions.

Best Answer

Related Solutions

MATLAB: Does a figure window open in the foreground in MATLAB 7.0 (R14) when I create the figure using Visual Basic

MATLAB: Does the Simulink model, which used to work fine in Simulink 4.0 (R12), return an error message “One or more output arguments not assigned during call” when executed in Simulink 6.0 (R14) and later versions

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