#include <stdio.h> and may also need some of #include <stdarg.h>, #include <sys/types.h>, #include <sys/stat.h>, #include <fcntl.h>.
int close (int handle ) - Close a file opened for unbuffered I/O.
int creat(char *filename, int pmode ) - Create a new file with specified permission setting.
int eof (int handle) - Check for end of file.
long lseek(int handle, long offset, int origin) - Go to a specific position in a file.
int open(char *filename, int oflag, unsigned pmode) - Open a file for low-level I/O.
int read(int handle, char *buffer, unsigned length) - Read binary data from a file into a buffer.
int Write(int handle, char *buffer, unsigned count ) - Write binary data from a buffer to a file.