https://devzone.nordicsemi.com/f/nordic-q-a/59100/segger-embedded-studio-build-a-project-with-a-lib-failedHi, I add a my .ilb file in the ses project .When I c all the function in the .lib file and build, it will have an log &quot;undefined reference to &#39;xxxx&#39;&quot;. But i can success in the keil project. What can i do to solve it? Thank you very mach.en-USTelligent Community 13Mon, 16 Mar 2020 01:09:50 GMThttps://devzone.nordicsemi.com/thread/239856?ContentTypeID=1Mon, 16 Mar 2020 01:09:50 GMT137ad170-7792-4731-bb38-c0d22fbe4515:fecbc989-6d0e-46f1-82d2-88f94c4bd5ee33<p>Thank you</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/239833?ContentTypeID=1Sat, 14 Mar 2020 19:39:13 GMT137ad170-7792-4731-bb38-c0d22fbe4515:5371dad7-5e7b-4c50-93b6-728276bb9dd4Nguyen Hoan Hoang<p>Keil .lib is incompatible. &nbsp;SES uses GCC. &nbsp;You need a GCC .a version of the lib you want to use.&nbsp;</p><div style="clear:both;"></div>