stat, lstat, fstat -- get file status
Standard C Library (libc, -lc)
#include <sys/types.h>
#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);
DESCRIPTION [Toc]
The stat() system call 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() system call 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() system call obtains the same information about an open file
known by the file descriptor fd.
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.
The time-related fields of struct stat are as follows:
st_atime Time when file data last accessed. Changed by the
mknod(2), utimes(2), read(2) and readv(2) system calls.
st_mtime Time when file data last modified. Changed by the
mkdir(2), mkfifo(2), mknod(2), utimes(2), write(2) and
writev(2) system calls.
st_ctime Time when file status was last changed (inode data modification).
Changed by the chflags(2), chmod(2), chown(2),
creat(2), link(2), mkdir(2), mkfifo(2), mknod(2),
rename(2), rmdir(2), symlink(2), truncate(2), unlink(2),
utimes(2), write(2) and writev(2) system calls.
st_birthtime Time when the inode was created.
If _POSIX_SOURCE is not defined, the time-related fields are defined as:
#ifndef _POSIX_SOURCE
#define st_atime st_atimespec.tv_sec
#define st_mtime st_mtimespec.tv_sec
#define st_ctime st_ctimespec.tv_sec
#endif
The size-related fields of the struct stat are as follows:
st_blksize The optimal I/O block size for the file.
st_blocks The actual number of blocks allocated for the file in
512-byte units. As short symbolic links are stored in the
inode, this number may be zero.
The status information word st_mode has the following bits:
#define S_IFMT 0170000 /* type of file */
#define S_IFIFO 0010000 /* named pipe (fifo) */
#define S_IFCHR 0020000 /* character special */
#define S_IFDIR 0040000 /* directory */
#define S_IFBLK 0060000 /* block special */
#define S_IFREG 0100000 /* regular */
#define S_IFLNK 0120000 /* symbolic link */
#define S_IFSOCK 0140000 /* socket */
#define S_IFWHT 0160000 /* whiteout */
#define S_ISUID 0004000 /* set user id on execution */
#define S_ISGID 0002000 /* set group id on execution */
#define S_ISVTX 0001000 /* save swapped text even after use */
#define S_IRUSR 0000400 /* read permission, owner */
#define S_IWUSR 0000200 /* write permission, owner */
#define S_IXUSR 0000100 /* execute/search permission, owner */
For a list of access modes, see <sys/stat.h>, access(2) and chmod(2).
RETURN VALUES [Toc]
Upon successful completion, the value 0 is returned; otherwise the
value -1 is returned and the global variable errno is set to indicate the
error.
COMPATIBILITY [Toc]
Previous versions of the system used different types for the st_dev,
st_uid, st_gid, st_rdev, st_size, st_blksize and st_blocks fields.
The stat() and lstat() system calls will fail if:
[EACCES] Search permission is denied for a component of the
path prefix.
[EFAULT] The sb or path argument points to an invalid address.
[EIO] An I/O error occurred while reading from or writing to
the file system.
[ELOOP] Too many symbolic links were encountered in translating
the pathname.
[ENAMETOOLONG] A component of a pathname exceeded 255 characters, or
an entire path name exceeded 1023 characters.
[ENOENT] The named file does not exist.
[ENOTDIR] A component of the path prefix is not a directory.
[EOVERFLOW] The file size in bytes cannot be represented correctly
in the structure pointed to by sb.
The fstat() system call will fail if:
[EBADF] The fd argument is not a valid open file descriptor.
[EFAULT] The sb argument points to an invalid address.
[EIO] An I/O error occurred while reading from or writing to
the file system.
[EOVERFLOW] The file size in bytes cannot be represented correctly
in the structure pointed to by sb.
access(2), chmod(2), chown(2), utimes(2), symlink(7)
Applying fstat() to a socket (and thus to a pipe) returns a zeroed
buffer, except for the blocksize field, and a unique device and inode
number.
The stat() and fstat() system calls are expected to conform to ISO/IEC
9945-1:1990 (``POSIX.1'').
The stat() and fstat() system calls appeared in Version 7 AT&T UNIX. The
lstat() system call appeared in 4.2BSD.
FreeBSD 5.2.1 February 15, 2002 FreeBSD 5.2.1