文件操作函数之fstat

1. 函数原型int fstat(int fd, struct stat *buf);
2. 需要包含头文件
       #include
       #include
       #include

3. 函数功能: These  functions return information about a file, 把一个文件的信息放在结构struct stat 中
    struct stat {
               dev_t     st_dev;     /* ID of device containing file */
               ino_t     st_ino;     /* inode number */
               mode_t    st_mode;    /* protection */
               nlink_t   st_nlink;   /* number of hard links */
               uid_t     st_uid;     /* user ID of owner */
               gid_t     st_gid;     /* group ID of owner */
               dev_t     st_rdev;    /* device ID (if special file) */
               off_t     st_size;    /* total size, in bytes */
               blksize_t st_blksize; /* blocksize for file system I/O */
               blkcnt_t  st_blocks;  /* number of 512B blocks allocated */
               time_t    st_atime;   /* time of last access */
               time_t    st_mtime;   /* time of last modification */
               time_t    st_ctime;   /* time of last status change */
           };

4. 函数返回值， On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.


5. exemple
     struct stat  fileAttribute;
    
     if(fstat(fd, &fileAttribute) < 0)
          printf("fstat func failed\n");

     printf("fd size :%d\n", fileAttribute.st_size);