I am trying to use the system() function from the stdlib.h, which further calls the [ int _EXFUN(system, (const char *__string) ] inside stdlib.h. However upon building the project, the complier shows an error [ Undefined reference to "_system" ], but i am pretty sure that it was already defined properly. Has anyone met this issue before? I am using SDK 2015.2. Need some advise! Thanks in Advance!