System Calls stat(2)
NAME
stat, lstat, fstat - get file status
SYNOPSIS
<sys/types.h>
<sys/stat.h>
int stat(const char *path, struct stat *buf);
int lstat(const char *path, struct stat *buf);
int fstat(int fildes, struct stat *buf);
DESCRIPTION
The stat() function obtains information about the file
pointed to by path. Read, write, or execute permission of
the named file is not required, but all directories listed
in the path name leading to the file must be searchable.
The lstat() function obtains file attributes similar to
stat(), except when the named file is a symbolic link; in
that case lstat() returns information about the link, while
stat() returns information about the file the link refer-
ences.
The fstat() function obtains information about an open file
known by the file descriptor fildes, obtained from a suc-
cessful open(2), creat(2), dup(2), fcntl(2), or pipe(2)
function.
The buf argument is a pointer to a stat structure into which
information is placed concerning the file. A stat structure
includes the following members:
mode_t st_mode; /* File mode (see mknod(2)) */
ino_t st_ino; /* Inode number */
dev_t st_dev; /* ID of device containing */
/* a directory entry for this file */
dev_t st_rdev; /* ID of device */
/* This entry is defined only for */
/* char special or block special files */
nlink_t st_nlink; /* Number of links */
uid_t st_uid; /* User ID of the file's owner */
gid_t st_gid; /* Group ID of the file's group */
off_t st_size; /* File size in bytes */
time_t st_atime; /* Time of last access */
time_t st_mtime; /* Time of last data modification */
time_t st_ctime; /* Time of last file status change */
/* Times measured in seconds since */
/* 00:00:00 UTC, Jan. 1, 1970 */
long st_blksize; /* Preferred I/O block size */
blkcnt_t st_blocks; /* Number of 512 byte blocks allocated*/
Descriptions of structure members are as follows:
st_mode
The mode of the file as described in mknod(2). In
addition to the modes described in mknod(), the mode
of a file may also be S_IFLNK if the file is a sym-
bolic link. S_IFLNK may only be returned by lstat().
st_ino
This field uniquely identifies the file in a given
file system. The pair st_ino and st_dev uniquely
identifies regular files.
st_dev
This field uniquely identifies the file system that
contains the file. Its value may be used as input to
the ustat() function to determine more information
about this file system. No other meaning is associated
with this value.
st_rdev
This field should be used only by administrative com-
mands. It is valid only for block special or character
special files and only has meaning on the system where
the file was configured.
st_nlink
This field should be used only by administrative com-
mands.
st_uid
The user ID of the file's owner.
st_gid
The group ID of the file's group.
st_size
For regular files, this is the address of the end of
the file. For block special or character special, this
is not defined. See also pipe(2).
st_atime
Time when file data was last accessed. Changed by the
following functions: creat(), mknod(), pipe(),
utime(2), and read(2).
st_mtime
Time when data was last modified. Changed by the fol-
lowing functions: creat(), mknod(), pipe(), utime(),
and write(2).
st_ctime
System Calls stat(2)
Time when file status was last changed. Changed by the
following functions: chmod(), chown(), creat(),
link(2), mknod(), pipe(), unlink(2), utime(), and
write().
st_blksize
A hint as to the "best" unit size for I/O operations.
This field is not defined for block special or charac-
ter special files.
st_blocks
The total number of physical blocks of size 512 bytes
actually allocated on disk. This field is not defined
for block special or character special files.
