emlc C code generation error "Unable to apply the reference parameter optimization"

I have a code base with several M functions I am converting to be included into an existing C code base. I am trying to limit the input by value overhead of large structures so created a glob structure. Some data is input, some output, some are persistent.

I have 2 functions which use this same global structure.

function [glob] = foo_gen
  Data = struct('Input',zeros(8,1),'Output',zeros(8,1),'State',zeros(1));
  eml.cstructname(Data,'DataStruct_t');
  glob = struct('AllData',repmat(Data,3,1));
  eml.cstructname(glob,'GlobalStruct_t');
end

function [glob] = foo(glob)

    eml.cstructname(glob,'GlobalStruct_t');
    eml.cstructname(glob.AllData(1),'DataStruct_t');

    glob.AllData(1).Output = glob.AllData(1).Input;
  end

I have many difficulties with getting this compile. Sometimes, it errors out that the tpyes do not match or is reused when the foo and foo_gen do not match exactly. It errors out if the foo function encapsulates the eml.cstructnames in an if ~isempty(eml.target) block.

I am using a multiple-entry point emlc invocation: emlc -c -s rtw_config -d ..\M_Code_Release foo -eg {glob} foo_gen

What does the error message "Unable to apply the reference parameter optimization to 'glob' of function 'foo'" mean and how do I fix it. The suggestion is to rewrite the code to not have outputs and inputs with matching names but my real code would be unworkable like that.

[John]

This is using Matlab 2010.

Answer 1

[Fred Smith]

This sounds like a bug. What version of MATLAB are you using?

Your example worked in the latest version of MATLAB after upgrading to the latest syntax:

.m:

 function [glob] = foo(glob)

 coder.cstructname(glob,'GlobalStruct_t');
 coder.cstructname(glob.AllData(1),'DataStruct_t');

 glob.AllData(1).Output = glob.AllData(1).Input;
 end

foo_gen.m:

 function [glob] = foo_gen
 Data = struct('Input',zeros(8,1),'Output',zeros(8,1),'State',zeros(1));
 coder.cstructname(Data,'DataStruct_t');
 glob = struct('AllData',repmat(Data,3,1));
 coder.cstructname(glob,'GlobalStruct_t');
 end

doit.m:

 glob = foo_gen;
 codegen -c -config:lib -d ..\M_Code_Release foo -args {glob} foo_gen

[John]

See Comment added to original question