C:/Users/SW/AppData/Local/Arduino15/packages/esp32/tools/esp-x32/2507/bin/../lib/gcc/xtensa-esp-elf/14.2.0/../../../../xtensa-esp-elf/bin/ld.exe: C:\Users\SW\AppData\Local\arduino\sketches\FAAFA66958F154FBB8F0FCE001A14209\sketch\JKBMS-WI.ino.cpp.o:(.literal._ZL18jk_notify_callbackP23BLERemoteCharacteristicPhjb+0x20): undefined reference to `Datenanalyse()'
C:/Users/SW/AppData/Local/Arduino15/packages/esp32/tools/esp-x32/2507/bin/../lib/gcc/xtensa-esp-elf/14.2.0/../../../../xtensa-esp-elf/bin/ld.exe: C:\Users\SW\AppData\Local\arduino\sketches\FAAFA66958F154FBB8F0FCE001A14209\sketch\JKBMS-WI.ino.cpp.o: in function `jk_notify_callback(BLERemoteCharacteristic*, unsigned char*, unsigned int, bool)':
H:\Arduino\JKBMS_MQtt_mitESP32\Forum_Akkudoctor\JKBMS-WI/BLE_BMS_Connection.ino:120:(.text._ZL18jk_notify_callbackP23BLERemoteCharacteristicPhjb+0x96): undefined reference to `Datenanalyse()'
collect2.exe: error: ld returned 1 exit status
exit status 1

Compilation error: exit status 1