https://devzone.nordicsemi.com/f/nordic-q-a/18020/mistake-in-sdk-headerIn nRF5_SDK_12.1.0_0d23e2a in file: ...\components\softdevice\common\softdevice_handler\ant_stack_handler_types.h In lines 30-32 inside #ifdef ANT_STACK_SUPPORT_REQD is preprocessor conditional witch extern &#39;C&#39; and parenthesis. But the same closing conditionalen-USTelligent Community 13Mon, 28 Nov 2016 14:12:08 GMThttps://devzone.nordicsemi.com/thread/69453?ContentTypeID=1Mon, 28 Nov 2016 14:12:08 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ba9360cb-3ce9-4189-9ae5-876374f5957bJ&#248;rgen Holmefjord<p>Hi,</p> <p>Thanks for reporting. This is a known issue, and is listed in the comments in the &quot;<a href="https://devzone.nordicsemi.com/question/93241/what-are-sdk-12x0-known-issues/"><em>What are SDK 12.x.0 known issues</em></a>&quot; thread.</p> <p>You can find a patch in <a href="https://devzone.nordicsemi.com/question/93241/what-are-sdk-12x0-known-issues/">this post</a>.</p> <p>Best regards,</p> <p>Jørgen</p><div style="clear:both;"></div>