Trying to include C file in C++ Projecthttps://devzone.nordicsemi.com/f/nordic-q-a/99144/trying-to-include-c-file-in-c-projectHi, I have created a C++ project for the edge impulse purpose. standalone its working and including my C files also working until I am not calling any C function from main cpp file. As I am calling any function error is coming like undefined referenceen-USTelligent Community 13Thu, 27 Apr 2023 16:14:27 GMTRE: Trying to include C file in C++ Projecthttps://devzone.nordicsemi.com/thread/422829?ContentTypeID=1Thu, 27 Apr 2023 16:14:27 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e1ff0930-c319-4779-95be-b4339ec1e331ovrebekk<p>Hi Sabir</p> <p>In order to call C functions from a C++ file you need to use the extern &quot;C&quot; declaration in the header of the C file, in order for the C++ linker to find the C functions.&nbsp;</p> <p>This is explained in more detail <a href="https://embeddedartistry.com/blog/2017/05/01/mixing-c-and-c-extern-c/">here</a>, and you can see how the extern &quot;C&quot; declaration is used in the various Zephyr headers <a href="https://github.com/nrfconnect/sdk-zephyr/blob/main/include/zephyr/bluetooth/gatt.h#L28-L30">here</a>.&nbsp;</p> <p>Best regards<br />Torbjørn</p><div style="clear:both;"></div>