I am new to freeRTOS. I went through tutorials to get c applications built and tested on a Xilinx ZC702 board (Cortex A9) and they work fine. I tried to create a very basic c++ application (hello world) but it will not link. Several objects are missing, including ulICCIAR, that are defined in port.c and referenced in portASM.s (this is where the linkage fails). I am using Xilinx SDK on Windows 7. I assume this is a name mangling problem or a toolchain setup problem but I have not been able to find help anywhere on the internet. I was hoping someone using freeRTOS might be able to assist me.

We don’t actually use C++ ourselves, but lot of people do use FreeRTOS in C++ applications, and even provide C++ frameworks. What we do do is have extern “C” in the header files of the core code to ensure the core code can be built as C in an otherwise C++ application. I don’t think this is the issue in this case though. ulICCIAR is declared in the relevant port.c source file, then used in portASM.S. I suspect the name is being mangled in the C file so the .S file cannot use the original name. Are you building the FreeRTOS source files as C code? It should then link in a C++ application. Regards.

I created the application as c++ and included the FreeRTOS code as-is in the application. The toolchain is set to g++ and the build log indicates the g++ compiler is used on port.c module. I thought the g++ compiler would treat c modules as c code and cc/cpp modules as c++ code. Is there a way to build the FreeRTOS modules separately and then just link them in as a module (like a lib)?

I changed the toolchain to use the gcc compiler (override g++) for every c module in the project and then added in the include paths for every c module as well. It then built with no linkage problems. There must be a way to change to gcc compiler and include paths for c modules only once at the top level of the project instead of having to override every c file independently but I could not find it in the Xilinx SDK. Anyhow the project finally builds… now I need to figure out why initializing basic hardware doesn’t work. Thanks for your help. Any other pointers would be appreciated.

Figured out why the basic hardware was not initializing… script.ld was generic and was missing the FreeRTOS vector table stuff. All good now.