ProgrammingProgramming LanguagesC ProgrammingSystem CallsOn this pageSystem CallsGeoffrey Huntermbedded.ninja AuthorMost standard C libraries depend on a number of subroutine calls for interacting with system services. These are called system calls. Standard C System Calls _exit() Exits a program without cleaning up files. close() Closes a file int close(int file) { return -1;}