Build fails for intermediate course L2 E4

[Mohammed Ubaid]

Hi,

I am trying to build memfault sample as in intermediate course, after hello_world project configuration and prj.conf options addition, i get following build error on nCS v2.9.0

/bin/cmake -E true
/opt/nordic/ncs/toolchains/b8efef2ad5/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: modules/memfault-firmware-sdk/lib..__modules__lib__memfault-firmware-sdk__ports__zephyr.a(memfault_metrics.c.obj): in function `prv_heartbeat_timer':
/opt/nordic/ncs/v2.9.0/modules/lib/memfault-firmware-sdk/components/metrics/src/memfault_metrics.c:843: undefined reference to `log_system_stats'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed. 

[Mohammed Ubaid]

Solved it, 

Needed in main.c:

void log_system_stats(void) {
  // Custom metric collection goes here
  // Example: memfault_metrics_heartbeat_set_unsigned(MEMFAULT_METRICS_KEY(BatteryLevel), battery_read());
}