CODECOMPOSER: Undefined symbol

Hi everyone,

I have a simple following code:

#include "device.h"
#include "driverlib.h"

void main(){
    Device_init();
}

The function Device_init() is defined in "device.h", and I have included it.

Why I still receive the following error:

**** Build of configuration Debug for project Test_I2C ****

"C:\\ti\\ccs1020\\ccs\\utils\\bin\\gmake" -k -j 20 all -O 
 
Building file: "../main.c"
Invoking: C2000 Compiler
"C:/ti/ccs1020/ccs/tools/compiler/ti-cgt-c2000_20.2.2.LTS/bin/cl2000" -v28 -ml -mt --cla_support=cla1 --float_support=fpu32 --tmu_support=tmu0 --vcu_support=vcu2 --include_path="C:/VietDucK19/CCS/I2c/Test_I2C" --include_path="C:/ti/c2000/C2000Ware_5_01_00_00/device_support/f2807x/common/include" --include_path="C:/ti/c2000/C2000Ware_5_01_00_00/device_support/f2807x/headers/include" --include_path="C:/ti/c2000/C2000Ware_5_01_00_00/driverlib/f2837xd/driverlib" --include_path="C:/ti/c2000/C2000Ware_5_01_00_00/driverlib/f2837xd/driverlib/inc" --include_path="C:/ti/ccs1020/ccs/tools/compiler/ti-cgt-c2000_20.2.2.LTS/include" -g --diag_warning=225 --diag_wrap=off --display_error_number --abi=coffabi --preproc_with_compile --preproc_dependency="main.d_raw"  "../main.c"
Finished building: "../main.c"
 
Building target: "Test_I2C.out"
Invoking: C2000 Linker
"C:/ti/ccs1020/ccs/tools/compiler/ti-cgt-c2000_20.2.2.LTS/bin/cl2000" -v28 -ml -mt --cla_support=cla1 --float_support=fpu32 --tmu_support=tmu0 --vcu_support=vcu2 -g --diag_warning=225 --diag_wrap=off --display_error_number --abi=coffabi -z -m"Test_I2C.map" --stack_size=0x200 --warn_sections -i"C:/ti/ccs1020/ccs/tools/compiler/ti-cgt-c2000_20.2.2.LTS/lib" -i"C:/ti/ccs1020/ccs/tools/compiler/ti-cgt-c2000_20.2.2.LTS/include" --reread_libs --diag_wrap=off --display_error_number --xml_link_info="Test_I2C_linkInfo.xml" --rom_model -o "Test_I2C.out" "./main.obj" "../2837x_FLASH_lnk_cpu1.cmd"  -llibc.a 
<Linking>
 
 undefined    first referenced
  symbol          in file     
 ---------    ----------------
 _Device_init ./main.obj      
 
error #10234-D: unresolved symbols remain
error #10010: errors encountered during linking; "Test_I2C.out" not built
 
>> Compilation failure
makefile:141: recipe for target 'Test_I2C.out' failed
gmake[1]: *** [Test_I2C.out] Error 1
makefile:137: recipe for target 'all' failed
gmake: *** [all] Error 2

**** Build Finished ****

Can someone help me, thank you in advance.