STAT(2) | System Calls Manual | STAT(2) |
stat
, lstat
,
fstat
, fstatat
—
#include <sys/stat.h>
int
stat
(const
char *path, struct stat
*sb);
int
lstat
(const
char *path, struct stat
*sb);
int
fstat
(int
fd, struct stat
*sb);
#include
<sys/stat.h>
#include <fcntl.h>
int
fstatat
(int
fd, const char
*path, struct stat
*sb, int flag);
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 function lstat
() is like
stat
() except in the case where the named file is a
symbolic link, in which case lstat
() returns
information about the link, while stat
() returns
information about the file the link references. The
fstat
() function obtains the same information about
an open file known by the file descriptor fd.
fstatat
() works the same way as
stat
() (or lstat
() if
AT_SYMLINK_NOFOLLOW
is set in
flag) except if path is
relative. In that case, it is looked up from a directory whose file
descriptor was passed as fd. Search permission is
required on this directory. fd can be set to
AT_FDCWD
in order to specify the current
directory.
The sb argument is a pointer to a
stat structure as defined by
<sys/stat.h>
and into which
information is placed concerning the file.
Type | Entry | Description |
dev_t | st_dev | device ID containing the file |
ino_t | st_ino | serial number of the file (inode number) |
mode_t | st_mode | mode of the file |
nlink_t | st_nlink | number of hard links to the file |
uid_t | st_uid | user ID of the owner |
gid_t | st_gid | group ID of the owner |
dev_t | st_rdev | device type (character or block special) |
off_t | st_size | size of the file 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 |
blksize_t | st_blksize | preferred I/O block size (fs-specific) |
blkcnt_t | st_blocks | blocks allocated for the file |
These are specified in the IEEE Std 1003.1-2004 (“POSIX.1”) standard. The st_ino and st_dev fields taken together uniquely identify the file within the system. Most of the types are defined in types(3).
The time-related fields are:
The size-related fields of the struct stat are as follows:
The status information word st_mode contains bits that define the access mode (see chmod(2)) and the type (see dirent(3)) of the file. The following macros can be used to test whether a file is of the specified type. The value m supplied to the macros is the value of st_mode.
S_ISBLK
(m)S_ISCHR
(m)S_ISDIR
(m)S_ISFIFO
(m)S_ISREG
(m)S_ISLNK
(m)S_ISSOCK
(m)The macros evaluate to a non-zero value if the test is true or to the value 0 if the test is false.
Type | Entry | Description |
long | st_atimensec | last access (nanoseconds) |
long | st_mtimensec | last modification (nanoseconds) |
long | st_ctimensec | last status change (nanoseconds) |
time_t | st_birthtime | time of inode creation |
long | st_birthtimensec | inode creation (nanoseconds) |
uint32_t | st_flags | user defined flags for the file |
uint32_t | st_gen | file generation number |
uint32_t | st_spare[2] | implementation detail |
However, if _NETBSD_SOURCE is furthermore defined, instead of the above, the following are present in the structure:
Type | Entry | Description |
struct timespec | st_atimespec | time of last access |
struct timespec | st_mtimespec | time of last modification |
struct timespec | st_birthtimespec | time of creation |
uint32_t | st_flags | user defined flags |
uint32_t | st_gen | file generation number |
uint32_t | st_spare[2] | implementation detail |
In this case the following macros are provided for convenience:
#if defined(_NETBSD_SOURCE) #define st_atime st_atimespec.tv_sec #define st_atimensec st_atimespec.tv_nsec #define st_mtime st_mtimespec.tv_sec #define st_mtimensec st_mtimespec.tv_nsec #define st_ctime st_ctimespec.tv_sec #define st_ctimensec st_ctimespec.tv_nsec #define st_birthtime st_birthtimespec.tv_sec #define st_birthtimensec st_birthtimespec.tv_nsec #endif
The status information word st_flags has the following bits:
Constant | Description |
UF_NODUMP |
do not dump a file |
UF_IMMUTABLE |
file may not be changed |
UF_APPEND |
writes to file may only append |
UF_OPAQUE |
directory is opaque wrt. union |
SF_ARCHIVED |
file is archived |
SF_IMMUTABLE |
file may not be changed |
SF_APPEND |
writes to file may only append |
For a description of the flags, see chflags(2).
stat
(), lstat
(),
fstat
(), and fstatat
()
functions return the value 0 if successful; otherwise the
value -1 is returned and the global variable
errno is set to indicate the error.
st_dev
, st_uid
,
st_gid
, st_rdev
,
st_size
, st_blksize
and
st_blocks
fields.
stat
(), lstat
() and
fstatat
() will fail if:
EACCES
]EBADF
]EFAULT
]EIO
]ELOOP
]ENAMETOOLONG
]NAME_MAX
}
characters, or an entire path name exceeded
{PATH_MAX
} characters.ENOENT
]ENOTDIR
]ENXIO
]In addition, fstatat
() will fail if:
EBADF
]AT_FDCWD
nor a
valid file descriptor open for reading or searching.ENOTDIR
]fstat
() will fail if:
stat
(), lstat
(), and
fstat
() conform to IEEE Std
1003.1-2004 (“POSIX.1”).
fstatat
() conforms to IEEE Std
1003.1-2008 (“POSIX.1”).
stat
() and fstat
() function
calls appeared in Version 1 AT&T UNIX. A
lstat
() function call appeared in
4.2BSD.
fstat
() to a socket (and thus to a pipe)
returns a zero'd buffer, except for the blocksize field, and a unique device
and file serial number.
September 1, 2019 | NetBSD 9.2 |