Undefined reference to `ssFxpSetU​32BitRegio​nCompliant​' and `ssRegiste​rDataTypeF​xpBinaryPo​int'

Hi,

I am trying to compile a MEX file from a set of C source code files from our project. In the output specification function of the S function, I have defined 64 bit output parameter.

I had created a legacy code C file which acts as a wrapper to the source code files and tried compiling it along with other source code files with the command mex src1.c src2.c, ..... etc..,

On compiling the mex file, I get Undefined reference to `ssFxpSetU32BitRegionCompliant' and Undefined reference to `ssRegisterDataTypeFxpBinaryPoint' errors.

I had inspected the legacy code generated C file and it already has the fixedpoint.h included which has the function definition for `ssFxpSetU32BitRegionCompliant' and `ssRegisterDataTypeFxpBinaryPoint'.

It is strange that there is error eventhough the fixedpoint.h file is included. I am using R2019b version.

Thanks

[Arvindh Ram Ganapathi Raman]

I had also added fixedpoint.c file into the S function C file, But I still get the same error.

[Danilo Teran]

Hi

could you solve it ? i have the same problem and dont know how to resolve it

thanks for your help =)

[Arvindh Ram Ganapathi Raman]

I couldn't solve it directly, I worked around by splitting 64 bit variables into 2 32 bit variables and working with that. Sadly I could find no help regarding this on the internet. Let me know if you solved it the right way somehow.

Answer 1

[Narvik]

Hi,

As per my understanding, you are trying to compile a MEX file and facing issues. The errors you are seeing “Undefined reference to ssFxpSetU32BitRegionCompliant” and “Undefined reference to ssRegisterDataTypeFxpBinaryPoint” typically indicate a linking problem. In C and C++, an “undefined reference” error occurs when the linker is unable to find the implementation of a function or a symbol.

Since you mentioned that you included the fixedpoint.c and fixedpoint.h files in your S-function, you can try passing an extra argument “lfixedpoint” to the mex command. For example:

>> mex sfun_user_fxp_asr.c -lfixedpoint 

The argument "-lfixedpoint" tells the MEX compiler to link against the fixedpoint library when creating the MEX-file. Refer to

matlabroot/toolbox/simulink/fixedandfloat/fxpdemos/mex_sfun_user_fxp_examples.m 

file for more information on the same.

The following documentation provides more information on creating MEX files:

https://www.mathworks.com/help/fixedpoint/ug/creating-mex-files.html

Hope this helps!