To query the array layout of a function at compile time, use coder.isColumnMajor or coder.isRowMajor. This query can be useful for specializing your generated code when it involves row-major and column-major functions. For example, consider this function:

function S = addMatrixRouted(A,B)
 if coder.isRowMajor
     %execute this code if row major
     S = addMatrix_OptimizedForRowMajor(A,B); 
 elseif coder.isColumnMajor
     %execute this code if column major
     S = addMatrix_OptimizedForColumnMajor(A,B);
 end

The function addMatrixRouted behaves differently depending on whether it uses row-major layout or column-major layout. The layout that the function uses, for example, can depend on whether it is called from a function that contains coder.rowMajor or coder.columnMajor. When addMatrixRouted uses row-major layout, it calls the addMatrix_OptimizedForRowMajor function, which has efficient memory access for row-major data. When the function uses column-major layout, it calls a version of the addMatrix function optimized for column-major data.

By using the query functions, the generated code for addMatrixRouted provides efficient memory access for either choice of array layout.

Consider the function bar:

function bar
coder.columnMajor;
x = magic(3);
if coder.isColumnMajor(x)
    fprintf('This will always be displayed in generated code.\n');
else
    fprintf('This will never be displayed in generated code.\n');
end
end

Generate code:

codegen bar

To run the MEX function, enter:

bar_mex