MATLAB: Do I get an ‘undefined reference to ‘_thefunction’ ‘ error while building the model containing a C S-function using Real-Time Workshop 7.6 (R2010b)

simulink coder

I want to create a standalone application from a basic Simulink model containing only an S-function. This S-function contains C code generated from an external source. For the standalone generation, I use Real-Time Workshop with the rsim.tlc system target file.
The generation fails due to undefined references to 3 functions.
These 3 functions appear in one of the .c/.h files used by the S-function anyway. In the MATLAB error message, their names are concatenated with an underscore sign ("_"). I don't know if it does matter. The error ends as follows:
C:/PROGRA~1/Matlab/r2010b\extern\lib\win32\lcc\libut.lib C:/PROGRA~1/Matlab/r2010b\extern\lib\win32\lcc\libmx.lib C:/PROGRA~1/Matlab/r2010b\extern\lib\win32\lcc\libmat.lib C:/PROGRA~1/Matlab/r2010b\extern\lib\win32\lcc\libmwsl_fileio.lib
global_sfct.obj .text: undefined reference to '_EIU_Global_init'
global_sfct.obj .text: undefined reference to '_EIU_Global_reset'
global_sfct.obj .text: undefined reference to '_EIU_Global'
gmake: * [../main_model.exe] Error 3
### Real-Time Workshop build procedure for model: 'main_model' aborted due to an error.

Best Answer

This error usually happens if Simulink cannot find the source files required by the S-function. Please check regarding the following:
- The sources files are in the same directory as the S-function source file.
- Specify these files names in the 'S-function modules' field. Enter the filenames only; do not use extensions or full pathnames, e.g., enter 'src src1', not 'src.c src1.c'.
For additional information for specifying additional source files, refer to the link below:
https://www.mathworks.com/help/rtw/ref/source-files.html
Related Question