Undefined function or variable in MATLAB

Question

I have a problem running my main function in MATLAB (the main program and calls other functions). Trying to run it gives me the error "??? Undefined function or variable 'max_x_address'". But, as you can see below, it has been declared as a global. This is really bothering me, so any help would be appreciated. (Do I have to modify my pathdef.m file? That is what the MATLAB troubleshooting says, but I followed some of the steps and it didn't help.)
The following is a skeleton of the program:

function Adaptive_Information
global HUBS, max_x_address, max_y_address;
.
.
max_x_address = 10;
.
.
end

Pursuit · Accepted Answer · 2012-04-01 04:55:35Z

4

You have to declare it global in every context that will use it. That is, add:

global max_x_address

To the beginning of each function which will use max_x_address, plus the base workspace (if needed).

answered Apr 1, 2012 at 4:55

Pursuit

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1 Comment

Joebevo Over a year ago

Thanks, although I was able to fix it. The solution turned out to be to avoid declaring multiple variables on the same line. (Strange behavior from MATLAB)

user3615647 · Accepted Answer · 2014-05-08 09:05:00Z

2

Actually the line

global HUBS, max_x_address, max_y_address;

does not declare three global variables. The comma is a statement or expression delimiter in Matlab as is the EOL or the semicolon. So Matlab reads the above as

global HUBS
max_x_address
max_y_address;

So what it does is to declare HUBS as global. Then it tries to retrieve the value of max_x_address and print it. Finally it would retrieve the value of max_y_address and throw it away.

The correct syntax to declare more than one global variable is to delimit them by spaces (see also the documentation):

global HUBS max_x_address max_y_address

answered May 8, 2014 at 9:05

user3615647

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