Please refer to the file "hello_sensor.c (WICED-Smart-SDK\Apps\hello_sensor)".
You only need to include the header file "spar_utils.h".
You can include the library by adding the below codes in your application's makefile:
LIBS += [LIB PATH]
Ex. If you want to use function rand() in "hello_sensor" application, you can add below codes in "makefile.mk (WICED-Smart-SDK\Apps\hello_sensor)"
LIBS += ../../Tools/ARM_GNU/lib/libc.a
Thank you very much, that solved my problem.