Along with returning a value with the return statement, C++ function signatures can return an output by utilizing pointers as input. Please follow the steps below for an overview of the process of returning multiple outputs using the MATLAB interface to C++:
1. Create a file called "foo.hpp" with the following contents:
int foo(int *val) {
*val = 1;
return 0;
}
2. Execute the following command in the MATLAB Command Window:
>> clibgen.generateLibraryDefinition("foo.hpp")
3. Three files should be generated: "definefoo.mlx", "definefoo.m", and "fooData.xm"l. Open the file, "definefoo.mlx" in the MATLAB Live Editor.
4. Uncomment the code in the section called: "C++ function foo with MATLAB name clib.foo.foo" and replace <SHAPE> with "1". Add the following line of code to the section of code that you just uncommented:
defineArgument(fooDefinition, "val", "int32", "output", 1);
5. Build the definition file, "define.mlx", by executing the following command in the MATLAB Command Window:
>> build(definefoo)
This will create a new folder called "foo" which contains "fooInterface.dll" which will be used by "clib" to interface with the "foo" C++ library
6. Click on the "addpath" link that is generated after you finish building the "foo" package. You can also do this yourself by using the "addpath" command in the MATLAB Command Window with the following syntax"
>> addpath('<path to "foo" folder>')
Where <path to "foo" folder> is replaced with the path to the "foo" folder generated after completing step 5.
7. Execute the following function in the MATLAB Command Window to show that you can receive multiple outputs from the MATLAB interface to C++ libraries:
>> [out1, out2] = clib.foo.foo
out1 =
int32
0
out2 =
int32
1
