MATLAB: Coder: Exclude/ignore code sections

Question

I'm using coder to generate C source code. Of course many matlab functions are not available for coder. But I still want to use these functions when running the code in matlab.

Currently I have to comment out all these sections that are not coder-friendly when doing C source code generation. Is there something I can wrap them in to make the coder ignore them?

Answer 1

You can wrap them with

if coder.target('MATLAB')
...
end

Or if that gives an error,

if isempty(coder.target)
...
end

You can also declare unsupported functions as "extrinsic" and use them in generated mex files. This practice has some pitfalls, and where unsupported data structures are involved, it can rather involved and advanced. However, in the simpler cases it is very simple. If foobar() is MATLAB function that you are passing, say, an m-by-n matrix to, and foobar returns, say, a 1-by-n vector (for example, this is what SUM would do with an m-by-n matrix where neither m nor n is 1), you would write:

coder.extrinsic('foobar');
y = zeros(1,size(x,2));
y = foobar(x);

Or, if you don't want to mess with coder.extrinsic:

y = zeros(1,size(x,2));
y = feval('foobar',x);

The y = zeros(...) line looks like wasted effort, but what it really does is tell the compiler what to expect by the next line, so it can copy the data from the MATLAB return into local storage. Basically, if you know what a function will return given the type of the input, then you just initialize the output variable to the appropriate type and then call the function.