#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
int stat(const char *path, struct stat *buf);
int fstat(int filedes, struct stat *buf);
int lstat(const char *path, struct stat *buf);
stat的定義：
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 filesystem I/O */
blkcnt_t st_blocks; /* number of 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 */
};
文件類型
S_ISREG(m) is it a regular file?
S_ISDIR(m) directory?
S_ISCHR(m) character device?
S_ISBLK(m) block device?
S_ISFIFO(m) FIFO (named pipe)?
S_ISLNK(m) symbolic link? (Not in POSIX.1-1996.)
S_ISSOCK(m) socket? (Not in POSIX.1-1996.)
函數說明 fstat()用來將參數fildes所指的文件狀態，複製到參數buf所指的
結構中(struct stat)。fstat()與stat()作用完全相同，不同處在
於傳入的參數爲已打開的文件描述詞。詳細內容請參考stat()。
返回值 執行成功則返回0，失敗返回-1，錯誤代碼存於errno。
設備號是16位的二進制，高八位主設備號(int)((unsigned short )a>>8)，第八位次設備號(int)((unsigned short )a&0xFF)
主設備號決定是用什麼驅動程序訪問設備，次設備號區分某一設備的各個類別如：
/dev/sda1
/dev/sda2
df命令訪問某文件分區
例：獲取某文件的文件狀態
int main(int arg, char *args[])
{
if (arg < 2)
{
printf("open file error");
return -1;
}
int fd = open(args[1], O_RDONLY);
if (fd == -1)
{
printf("error occur %s\n", strerror(errno));
} else
{
printf("the fd = %d\n", fd);
struct stat tmp;
int i = stat(args[1],&tmp);
if(i==-1)
{
printf("error\n");
close(fd);
return -1;
}
else
{
if(S_ISREG(tmp.st_mode))
printf("S_ISREG\n");
printf("%d\n",S_ISDIR(tmp.st_mode));
printf("%d\n",tmp.st_uid);
}
close(fd);
}
return 0;
}