error associated with Nargin

I download Matlab code and it worked well in an old version of Matlab. However, when I run it in Matlab R2017b I get an error message related to nargin. It says, you can only call nargin/narginout from within MatLab function.

[Image Analyst]

OK. Do you have a question? You've included neither the error message nor the code, so what can we say?

Answer 1

[Rik]

I just tested to confirm. For some odd reason you could use the nargin function in a script m-file. This returned the value for the calling function. The solution is to actually use the nargin function in a context it makes sense: a function.

The release notes also say this:

Move calls to nargin, nargout, and inputname into the relevant function file. If you need the results in a script, call the functions and store the results in a variable. Then use the variable in the script.

Answer 2

[Walter Roberson]

This was a change as of R2016b. Before that, if you called nargin from inside a script it would not error but would return 0; as of R2016b it errors.

There was never a great reason to call nargin from inside a script; about the only use for it was that if you temporarily commented out a function line so that variables would not disappear when the function exited, then you did not have to change nargin references.

You should either add a function header to the code to convert it to a function (in which nargin is a meaningful thing to query), or else you should replace the nargin with 0 (and potentially clean up the code afterwards.)

[Rik]

When I tested it, I got seemingly random numbers. For example, calling a file with only disp(nargin) inside it results in 123863040 (win10x64, R2012b). In 6.5 it results in -2.1475e+009.

But to be fair, I called the file directly, not from inside another function.

[Walter Roberson]

Hmmm, not much pattern on OS-X version

• R2010bSP1 -> 1
• R2011a -> 32767 (0x7FFF)
• R2011b -> 32767 (0x7FFF)
• R2012a -> -483851947 (0xE3290155)
• R2012b -> 28672 (0x7000)
• R2013a -> 28672 (0x7000)
• R2013b -> 0
• R2014a -> 32711 (0x7FC7)
• R2014b -> 28672 (0x7000)
• R2015aSP1 -> 32640 (0x7F80)
• R2015b -> errors already even though release notes for R2016a say it should still run
• R2016a -> errors already even though release notes for R2016a say it should still run