fstat()
PROTOTYPE
#include <posix.h>
int fstat(int fid, struct stat *info);
DESCRIPTION
fstat() writes information about the open file specified by file descriptor fid to the stat structure indicated by info. The stat structure is defined in “posix.h” and reproduced below:
struct stat
{
dev_t st_dev; /* ID of device containing this file */
ino_t st_ino; /* file serial number */
nlink_t st_nlink; /* number of links */
dev_t st_rdev; /* device ID (if inode device) */
off_t st_size; /* the file size in bytes */
time_t st_atime; /* last data access time (secs since Epoch) */
time_t st_mtime; /* last data modification time (secs since Epoch) */
time_t st_ctime; /* last status change time (secs since Epoch) */
mode_t st_mode; /* file mode */
uid_t st_uid; /* user ID of file's owner */
gid_t st_gid; /* group ID of file's owner */
};
“posix.h” defines macros that can be applied to the st_mode field to determine the file’s access permissions and mode. The S_ISDIR() and S_ISREG() macros test whether the file is a directory or regular file.
For directories, the st_size field is set to zero. frstat() behaves like fstat() except if the file is a directory, the st_size field is the sum of the size of every regular file in the directory and its subdirectories. Because of the recursive size calculation, frstat() takes longer to execute than fstat().
If successful, fstat() returns 0. Otherwise, it sets errno and returns -1.
ERROR CODES
| EBADF | fid is not the descriptor of an open file. |
| EFAULT | info equals NULL. |
EXAMPLE
struct stat info;
...
if (fstat(fid, &info))
error("fstat() failed");
else
{
printf("File data access time: %s", ctime(&info.st_atime));
printf("File data modified time: %s", ctime(&info.st_mtime));
if (vol_type == FAT_VOL)
printf("File creation time: %s", ctime(&info.st_ctime));
else
printf("File status change time: %s", ctime(&info.st_ctime));
printf("File mode: 0%o\n", info.st_mode);
printf("File serial number: %u\n", (uint)info.st_ino);
printf("File num links: %u\n", (uint)info.st_nlink);
printf("File size (byte): %'d\n", (int)info.st_size);
printf("File user ID: %u\n", info.st_uid);
printf("File group ID: %u\n", info.st_gid);
}