Error: L6218E: Undefined symbol main.o

Hi,

I am facing a linker error ".\STM32F4xx-Nucleo\DMA_LP_App.axf: Error: L6218E: Undefined symbol HAL_UART_Init (referred from main.o)."

I have added the file "stm32f4xx_hal_uart.c" and its path in option -> C/C++ -> include path but it's still showing the error.

If I add the file twice it shows ".\STM32F4xx-Nucleo\DMA_LP_App.axf: Error: L6200E: Symbol __asm___20_stm32f4xx_hal_uart_c____REV16 multiply defined (by stm32f4xx_hal_uart_1.o and stm32f4xx_hal_uart.o)."

Kindly let me what is causing this issue and what is possible solution.

Looking forward for kind cooperation.

Have a nice day!

Kind Regards, Ghalib