C system call test

#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include<sys/stat.h>

int main()
{
  // the system call useful in IO

    open():
    read():
    write():
    close();
    ioctl(); 

  //the final variable useful in IO
  //about open
  O_WRONLY | O_RDONLY | O_RDWR | O_APPEND | O_TRUNC | O_CREAT | O_EXCL

  //about create file
  S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IWOTH | S_IXOTH

}