Table of Contents

Compatibility Guidelines for MATLAB Coder

Table of Contents

Introduction

• Function calls
• Editor warnings
• Error function
• Pause function
• Struct manipulation
• Dynamic fields
• If else
• Switch otherwise
• Short-circuit operators
• Functionality shadowing
• Shell escape function
• Scripts
• Parentheses for precedence
• Floating-point comparisons
• Binary expressions
• Concatenate array

Introduction

The goal of this set of coding standards that can be automatically checked is to help you write MATLAB code that is Coder-compatible. The resulting code will be more suitable for code generation. For more information on MATLAB Coder, see the MathWorks website.

If you are looking for more generic coding standards that are not specifically aimed at Coder-compatibility, see our MonkeyProof Coding Standard for MATLAB.

Automatic compliance checking

The coding standards described here can be checked using CC4M by MonkeyProof Solutions. They are configured in the predefined CoderCompatibility configurations set available with the tool. For instructions on how to check your code against coding standards, see the video below. The steps are also described below the video.

You can check your code for compliance with the guidelines described here as follows:

1. Get CC4M and install per installation instructions.
2. Open CC4M in one of two ways:
   • Click the shortcut created at the top of the screen next to the documentation search bar: .
   • Run monkeyproof.cc4m.start() from the command window.
3. Select whether you want to check one or more files, all files in a folder, or all files in a MATLAB Project.
4. Select what files/folder/project to check.
5. Further customization is available, for example checking a folder including or excluding all subfolders.
6. Click the Run button at the bottom to start checking your code.

The guidelines that require human judgment or are simply not possible to check statically in MATLAB are not described here.

Guideline template

Every guideline is structured as follows:

Guideline name

Coder-compatibility function calls

Editor warnings

Error function

Pause function

Struct manipulation

Dynamic fields

If else

Switch otherwise

Avoid:

switch reply
    case "Yes"
        saveData()
    case "No"
        clearData()
end

Instead use:

switch reply
    case "Yes"
        msg = "ok";
        saveData()
    case "No"
        msg = "ok";
        clearData()
    otherwise
        % Should not get here.
        msg = "wrong reply";
end

Short-circuit operators

Avoid:

test1 = a > b;
test2 = b < a.^2;

result = test1 || test2;

Above will not work for vector values for a and b. Use elementwise logical operator | instead.

Instead use:

result = test1 | test2;

Functionality shadowing

Shell escape function

Scripts

Parentheses for precedence

Floating-point comparisons

Avoid:

out = myFcn(in) == sqrt(3);

Instead use:

out = abs(myFcn(in) - sqrt(3)) < 1e-12;

Binary expressions

avoid

 if (aFcnCall(z) || anotherFcnCall(z))

instead use

First compute the intermediate results in desired order:

isApprovedForA = aFcnCall(z); 
isApprovedForB = anotherFcnCall(z); 

 if (isApprovedForA || isApprovedForB)

or in case you really need the conditional execution:

isApproved = aFcnCall(z); 

if (~isApproved)
   % not yet approved
   isApproved = anotherFcnCall(z); 
else
   % allready approved
end

if (isApproved)

Concatenate array

Avoid:

a = [myStruct(:).b];

Instead use:

len = numel(myStruct);
a   = zeros(len);

for iMyStruct = 1:len
  a(iMyStruct) = myStruct(iMyStruct).b;
end