Do I need to recompile MEX if I edit a function?

Let's say I have a MATLAB function "fun1", which calls another MATLAB function "fun2".

I then run the MATLAB Coder on fun1 and compile it into MEX code. Then later, I edit fun2. Does fun1 need to be recompiled again?

I am in this situation now and after editing fun2, it seems that fun1 is still running fast and its outputs reflects the changes made in fun2. But I want to be sure that I do or don't have to recompile fun1 again.

Answer 1

[Darshan Ramakant Bhat]

When you generate code for "fun1" (which is called as "entry-point function" in code generation terminology), codes will be generated for underlying functions as well in a recursive manner.

So if you modify any function which is called from entry point function, the MEX needs to be re-compiled.

Special Case :

The above mentioned details are not true when you call a function by making it "extrinsic" function. Coder pragma coder.extrinsic is used to declare a function as extrinsic :

https://www.mathworks.com/help/simulink/slref/coder.extrinsic.html

When you declare a function as extrinsic, the generated code will call back to MATLAB to execute the function in MATLAB. So if you modify a function which is extrinsic, it may take effect without recompiling as well. But declaring a function as extrinsic will come with a performance hit.