Compiling C S-Function in MATLAB multiple definition error?

Question

I am trying to compile various C-Functions in MATLAB Simulink using the S-function builder block and the minGW 64bit Compiler. A syntax error in the code is impossible since it is code from an ECU which is in production and running for years. I keep getting the following error message with two of my files: > ...example.obj:example.c:(.text+0x0): multiple definition of `example' > ...example.obj:example.c:(.text+0x0): first defined here The error confuses me since it is referring to the same position as the "first definition". In the other functions it is position (`.text+0x17a`). Has any of you guys faced the same problem or any idea how to fix it? Can it be a bug of the compiler? Greetings from Germany, Jonathan

Answer 1

The error message you're seeing suggests that there's a multiple definition problem. Even if the code is from an ECU in production, it doesn't necessarily mean that it will compile seamlessly in every environment. The issue might arise due to differences in how the ECU compiler and the minGW compiler manage certain aspects of the code.

Here are some steps to troubleshoot:

Double Compilation: Make sure that the file is not being compiled twice or linked twice in your build process. For example, ensure that the file isn't added twice in your project or makefile.

Include Guards: If you're including C files using #include "example.c" (instead of using headers), it can lead to multiple definition errors. Always use header files (example.h) for declarations and C files (example.c) for definitions. Also, use include guards or #pragma once in your header files to prevent double inclusion: