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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 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 fstatat() system call is equivalent to stat() and lstat() except in the case where the
     path specifies a relative path.  In this case the status 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_atim      Time when file data last accessed.  Changed by the mknod(2), utimes(2), read(2)
                  and readv(2) system calls.

     st_mtim      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_ctim      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_birthtim  Time when the inode was created.

     The following time-related macros are defined for compatibility:

     #define st_atime                st_atim.tv_sec
     #define st_mtime                st_mtim.tv_sec
     #define st_ctime                st_ctim.tv_sec
     #ifndef _POSIX_SOURCE
     #define st_birthtime            st_birthtim.tv_sec
     #endif

     #ifndef _POSIX_SOURCE
     #define st_atimespec            st_atim
     #define st_mtimespec            st_mtim
     #define st_ctimespec            st_ctim
     #define st_birthtimespec        st_birthtim
     #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 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.

     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), sticky(7), symlink(7)

STANDARDS

     The stat() and fstat() system calls are expected to conform to ISO/IEC 9945-1:1990
     (“POSIX.1”).  The fstatat() 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 appeared in FreeBSD 8.0.

BUGS

     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.