STAT(2)

NAME
stat, lstat, fstat - get file status

LIBRARY
libc

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);

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 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

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.

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

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.

STANDARDS
The stat() and fstat() system calls are expected to conform to p1003.1-90.

HISTORY
The stat() and fstat() system calls appeared in AT&T UNIX. The lstat() system call appeared in 4.2BSD.