[Linux]基础IO[open, write, read]

1. open

2. write

  1 #include <stdio.h>
  2 #include <unistd.h>
  3 #include <sys/types.h>
  4 #include <sys/stat.h>
  5 #include <fcntl.h>
  6 #include <string.h>
  7 int main()
  8 {
  9     int fd;
 10     umask(0);
 11     const char* filename = "/home/test/a.txt";
 12     fd = open(filename, O_RDWR|O_APPEND, 0664);
 13     if (fd < 0)
 14     {
 15         perror("open error!");
 16         return -1;
 17     }
 18     char string[] = "hello IO!\n"; 
 19     const char* buf = "good!\n";
 20     write(fd, string, strlen(buf));
 21     write(fd, string, strlen(string));
 22     close(fd);
 23     return 0;
 24 }

3. read

  1 #include <stdio.h>                                                                                    
  2 #include <sys/types.h>
  3 #include <sys/stat.h>
  4 #include <fcntl.h>
  5 #include <unistd.h>
  6 #include <string.h>
  7 
  8 int main()
  9 {
 10     int fd = open("/home/test/a.txt", O_RDONLY);
 11     if (fd < 0)
 12     {
 13         perror("open error");
 14         return -1;
 15     }
 16     char buf[1024] = "";
 17     while(1)
 18     {
 19         ssize_t s = read(fd, buf, 1);
 20         if (s > 0)
 21         {
 22             printf("%s", buf);
 23         }
 24         else
 25         {
 26             break;
 27         }
 28     }
 29     close(fd);
 30 
 31     return 0;
 32 }           

4. 其他