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STAT(2)			    BSD	System Calls Manual		       STAT(2)

NAME
     stat, lstat, fstat, fstatat -- get	file status

LIBRARY
     Standard C	Library	(libc, -lc)

SYNOPSIS
     #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);

     int
     fstatat(int fd, const char	*path, struct stat *buf, int flag);

DESCRIPTION
     The stat()	system call obtains information	about the file pointed to by
     path.  Read, write	or execute permission of the named file	is not re-
     quired, 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	refer-
     ences.

     The fstat() system	call obtains the same information about	an open	file
     known by the file descriptor fd.

     The fstatat() system call is equivalent to	stat() and lstat() except in
     the case where the	path specifies a relative path.	 In this case the sta-
     tus is retrieved from a file relative to the directory associated with
     the file descriptor fd instead of the current working directory.

     The values	for the	flag are constructed by	a bitwise-inclusive OR of
     flags from	the following list, defined in <fcntl.h>:

     AT_SYMLINK_NOFOLLOW
	     If	path names a symbolic link, the	status of the symbolic link is
	     returned.

     If	fstatat() is passed the	special	value AT_FDCWD in the fd parameter,
     the current working directory is used and the behavior is identical to a
     call to stat() or lstat() respectively, depending on whether or not the
     AT_SYMLINK_NOFOLLOW bit is	set in flag.

     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 fields	of struct stat related to the file system are as follows:

     st_dev    The numeric ID of the device containing the file.

     st_ino    The file's inode	number.

     st_nlink  The number of hard links	to the file.

     The st_dev	and st_ino fields together identify the	file uniquely within
     the system.

     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 modifi-
		   cation).  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_size	 The file size in bytes.

     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 access-related	fields of struct stat are as follows:

     st_uid   The user ID of the file's	owner.

     st_gid   The group	ID of the file.

     st_mode  Status of	the file (see below).

     The status	information word st_mode has the following bits:

     #define S_IFMT   0170000  /* type of file mask */
     #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_IRWXU  0000700  /* RWX mask for owner */
     #define S_IRUSR  0000400  /* read permission, owner */
     #define S_IWUSR  0000200  /* write	permission, owner */
     #define S_IXUSR  0000100  /* execute/search permission, owner */
     #define S_IRWXG  0000070  /* RWX mask for group */
     #define S_IRGRP  0000040  /* read permission, group */
     #define S_IWGRP  0000020  /* write	permission, group */
     #define S_IXGRP  0000010  /* execute/search permission, group */
     #define S_IRWXO  0000007  /* RWX mask for other */
     #define S_IROTH  0000004  /* read permission, other */
     #define S_IWOTH  0000002  /* write	permission, other */
     #define S_IXOTH  0000001  /* execute/search permission, other */

     For a list	of access modes, see <sys/stat.h>, access(2) and chmod(2).
     The following macros are available	to test	whether	a st_mode value	passed
     in	the m argument corresponds to a	file of	the specified type:

     S_ISBLK(m)	  Test for a block special file.

     S_ISCHR(m)	  Test for a character special file.

     S_ISDIR(m)	  Test for a directory.

     S_ISFIFO(m)  Test for a pipe or FIFO special file.

     S_ISLNK(m)	  Test for a symbolic link.

     S_ISREG(m)	  Test for a regular file.

     S_ISSOCK(m)  Test for a socket.

     S_ISWHT(m)	  Test for a whiteout.

     The macros	evaluate to a non-zero value if	the test is true or to the
     value 0 if	the test is false.

RETURN VALUES
     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
     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.

ERRORS
     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 translat-
			ing 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.

     In	addition to the	errors returned	by the lstat(),	the fstatat() may fail
     if:

     [EBADF]		The path argument does not specify an absolute path
			and the	fd argument is neither AT_FDCWD	nor a valid
			file descriptor	open for searching.

     [EINVAL]		The value of the flag argument is not valid.

     [ENOTDIR]		The path argument is not an absolute path and fd is
			neither	AT_FDCWD nor a file descriptor associated with
			a directory.

SEE ALSO
     access(2),	chmod(2), chown(2), fhstat(2), statfs(2), utimes(2),
     symlink(7), sticky(8)

STANDARDS
     The stat()	and fstat() system calls are expected to conform to ISO/IEC
     9945-1:1990 ("POSIX.1").  The fchownat() system call follows The Open
     Group Extended API	Set 2 specification.

HISTORY
     The stat()	and fstat() system calls appeared in Version 7 AT&T UNIX.  The
     lstat() system call appeared in 4.2BSD.  The fstatat() system call	ap-
     peared in FreeBSD 8.0.

BUGS
     Applying fstat() to a socket (and thus to a pipe) returns a zeroed	buf-
     fer, except for the blocksize field, and a	unique device and inode	num-
     ber.

BSD				April 10, 2008				   BSD

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | COMPATIBILITY | ERRORS | SEE ALSO | STANDARDS | HISTORY | BUGS

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