STAT(2)                     Linux Programmer's Manual                    STAT(2)

       stat, fstat, lstat, fstatat - get file status

       #include <sys/stat.h>

       int stat(const char *restrict pathname,
                struct stat *restrict statbuf);
       int fstat(int fd, struct stat *statbuf);
       int lstat(const char *restrict pathname,
                struct stat *restrict statbuf);

       #include <fcntl.h>           /* Definition of AT_* constants */
       #include <sys/stat.h>

       int fstatat(int dirfd, const char *restrict pathname,
                struct stat *restrict statbuf, int flags);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

           /* Since glibc 2.20 */ _DEFAULT_SOURCE
               || _XOPEN_SOURCE >= 500
               || /* Since glibc 2.10: */ _POSIX_C_SOURCE >= 200112L
               || /* Glibc 2.19 and earlier */ _BSD_SOURCE

           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:

       These functions return information about a file, in the buffer pointed to
       by statbuf.  No permissions are required on the file itself, but—in the
       case of stat(), fstatat(), and lstat()—execute (search) permission is
       required on all of the directories in pathname that lead to the file.

       stat() and fstatat() retrieve information about the file pointed to by
       pathname; the differences for fstatat() are described below.

       lstat() is identical to stat(), except that if pathname is a symbolic
       link, then it returns information about the link itself, not the file
       that the link refers to.

       fstat() is identical to stat(), except that the file about which
       information is to be retrieved is specified by the file descriptor fd.

   The stat structure
       All of these system calls return a stat structure, which contains the
       following fields:

           struct stat {
               dev_t     st_dev;         /* ID of device containing file */
               ino_t     st_ino;         /* Inode number */
               mode_t    st_mode;        /* File type and mode */
               nlink_t   st_nlink;       /* Number of hard links */
               uid_t     st_uid;         /* User ID of owner */
               gid_t     st_gid;         /* Group ID of owner */
               dev_t     st_rdev;        /* Device ID (if special file) */
               off_t     st_size;        /* Total size, in bytes */
               blksize_t st_blksize;     /* Block size for filesystem I/O */
               blkcnt_t  st_blocks;      /* Number of 512B blocks allocated */

               /* Since Linux 2.6, the kernel supports nanosecond
                  precision for the following timestamp fields.
                  For the details before Linux 2.6, see NOTES. */

               struct timespec st_atim;  /* Time of last access */
               struct timespec st_mtim;  /* Time of last modification */
               struct timespec st_ctim;  /* Time of last status change */

           #define st_atime st_atim.tv_sec      /* Backward compatibility */
           #define st_mtime st_mtim.tv_sec
           #define st_ctime st_ctim.tv_sec

       Note: the order of fields in the stat structure varies somewhat across
       architectures.  In addition, the definition above does not show the
       padding bytes that may be present between some fields on various
       architectures.  Consult the glibc and kernel source code if you need to
       know the details.

       Note: for performance and simplicity reasons, different fields in the
       stat structure may contain state information from different moments
       during the execution of the system call.  For example, if st_mode or
       st_uid is changed by another process by calling chmod(2) or chown(2),
       stat() might return the old st_mode together with the new st_uid, or the
       old st_uid together with the new st_mode.

       The fields in the stat structure are as follows:

       st_dev This field describes the device on which this file resides.  (The
              major(3) and minor(3) macros may be useful to decompose the device
              ID in this field.)

       st_ino This field contains the file's inode number.

              This field contains the file type and mode.  See inode(7) for
              further information.

              This field contains the number of hard links to the file.

       st_uid This field contains the user ID of the owner of the file.

       st_gid This field contains the ID of the group owner of the file.

              This field describes the device that this file (inode) represents.

              This field gives the size of the file (if it is a regular file or
              a symbolic link) in bytes.  The size of a symbolic link is the
              length of the pathname it contains, without a terminating null

              This field gives the "preferred" block size for efficient
              filesystem I/O.

              This field indicates the number of blocks allocated to the file,
              in 512-byte units.  (This may be smaller than st_size/512 when the
              file has holes.)

              This is the time of the last access of file data.

              This is the time of last modification of file data.

              This is the file's last status change timestamp (time of last
              change to the inode).

       For further information on the above fields, see inode(7).

       The fstatat() system call is a more general interface for accessing file
       information which can still provide exactly the behavior of each of
       stat(), lstat(), and fstat().

       If the pathname given in pathname is relative, then it is interpreted
       relative to the directory referred to by the file descriptor dirfd
       (rather than relative to the current working directory of the calling
       process, as is done by stat() and lstat() for a relative pathname).

       If pathname is relative and dirfd is the special value AT_FDCWD, then
       pathname is interpreted relative to the current working directory of the
       calling process (like stat() and lstat()).

       If pathname is absolute, then dirfd is ignored.

       flags can either be 0, or include one or more of the following flags

       AT_EMPTY_PATH (since Linux 2.6.39)
              If pathname is an empty string, operate on the file referred to by
              dirfd (which may have been obtained using the open(2) O_PATH
              flag).  In this case, dirfd can refer to any type of file, not
              just a directory, and the behavior of fstatat() is similar to that
              of fstat().  If dirfd is AT_FDCWD, the call operates on the
              current working directory.  This flag is Linux-specific; define
              _GNU_SOURCE to obtain its definition.

       AT_NO_AUTOMOUNT (since Linux 2.6.38)
              Don't automount the terminal ("basename") component of pathname if
              it is a directory that is an automount point.  This allows the
              caller to gather attributes of an automount point (rather than the
              location it would mount).  Since Linux 4.14, also don't
              instantiate a nonexistent name in an on-demand directory such as
              used for automounter indirect maps.  This flag has no effect if
              the mount point has already been mounted over.

              Both stat() and lstat() act as though AT_NO_AUTOMOUNT was set.

              The AT_NO_AUTOMOUNT can be used in tools that scan directories to
              prevent mass-automounting of a directory of automount points.

              This flag is Linux-specific; define _GNU_SOURCE to obtain its

              If pathname is a symbolic link, do not dereference it: instead
              return information about the link itself, like lstat().  (By
              default, fstatat() dereferences symbolic links, like stat().)

       See openat(2) for an explanation of the need for fstatat().

       On success, zero is returned.  On error, -1 is returned, and errno is set
       to indicate the error.

       EACCES Search permission is denied for one of the directories in the path
              prefix of pathname.  (See also path_resolution(7).)

       EBADF  fd is not a valid open file descriptor.

       EBADF  (fstatat()) pathname is relative but dirfd is neither AT_FDCWD nor
              a valid file descriptor.

       EFAULT Bad address.

       EINVAL (fstatat()) Invalid flag specified in flags.

       ELOOP  Too many symbolic links encountered while traversing the path.

              pathname is too long.

       ENOENT A component of pathname does not exist or is a dangling symbolic

       ENOENT pathname is an empty string and AT_EMPTY_PATH was not specified in

       ENOMEM Out of memory (i.e., kernel memory).

              A component of the path prefix of pathname is not a directory.

              (fstatat()) pathname is relative and dirfd is a file descriptor
              referring to a file other than a directory.

              pathname or fd refers to a file whose size, inode number, or
              number of blocks cannot be represented in, respectively, the types
              off_t, ino_t, or blkcnt_t.  This error can occur when, for
              example, an application compiled on a 32-bit platform without
              -D_FILE_OFFSET_BITS=64 calls stat() on a file whose size exceeds
              (1<<31)-1 bytes.

       fstatat() was added to Linux in kernel 2.6.16; library support was added
       to glibc in version 2.4.

       stat(), fstat(), lstat(): SVr4, 4.3BSD, POSIX.1-2001, POSIX.1.2008.

       fstatat(): POSIX.1-2008.

       According to POSIX.1-2001, lstat() on a symbolic link need return valid
       information only in the st_size field and the file type of the st_mode
       field of the stat structure.  POSIX.1-2008 tightens the specification,
       requiring lstat() to return valid information in all fields except the
       mode bits in st_mode.

       Use of the st_blocks and st_blksize fields may be less portable.  (They
       were introduced in BSD.  The interpretation differs between systems, and
       possibly on a single system when NFS mounts are involved.)

   Timestamp fields
       Older kernels and older standards did not support nanosecond timestamp
       fields.  Instead, there were three timestamp fields—st_atime, st_mtime,
       and st_ctime—typed as time_t that recorded timestamps with one-second

       Since kernel 2.5.48, the stat structure supports nanosecond resolution
       for the three file timestamp fields.  The nanosecond components of each
       timestamp are available via names of the form st_atim.tv_nsec, if
       suitable feature test macros are defined.  Nanosecond timestamps were
       standardized in POSIX.1-2008, and, starting with version 2.12, glibc
       exposes the nanosecond component names if _POSIX_C_SOURCE is defined with
       the value 200809L or greater, or _XOPEN_SOURCE is defined with the value
       700 or greater.  Up to and including glibc 2.19, the definitions of the
       nanoseconds components are also defined if _BSD_SOURCE or _SVID_SOURCE is
       defined.  If none of the aforementioned macros are defined, then the
       nanosecond values are exposed with names of the form st_atimensec.

   C library/kernel differences
       Over time, increases in the size of the stat structure have led to three
       successive versions of stat(): sys_stat() (slot __NR_oldstat),
       sys_newstat() (slot __NR_stat), and sys_stat64() (slot __NR_stat64) on
       32-bit platforms such as i386.  The first two versions were already
       present in Linux 1.0 (albeit with different names); the last was added in
       Linux 2.4.  Similar remarks apply for fstat() and lstat().

       The kernel-internal versions of the stat structure dealt with by the
       different versions are, respectively:

              The original structure, with rather narrow fields, and no padding.

       stat   Larger st_ino field and padding added to various parts of the
              structure to allow for future expansion.

       stat64 Even larger st_ino field, larger st_uid and st_gid fields to
              accommodate the Linux-2.4 expansion of UIDs and GIDs to 32 bits,
              and various other enlarged fields and further padding in the
              structure.  (Various padding bytes were eventually consumed in
              Linux 2.6, with the advent of 32-bit device IDs and nanosecond
              components for the timestamp fields.)

       The glibc stat() wrapper function hides these details from applications,
       invoking the most recent version of the system call provided by the
       kernel, and repacking the returned information if required for old

       On modern 64-bit systems, life is simpler: there is a single stat()
       system call and the kernel deals with a stat structure that contains
       fields of a sufficient size.

       The underlying system call employed by the glibc fstatat() wrapper
       function is actually called fstatat64() or, on some architectures,

       The following program calls lstat() and displays selected fields in the
       returned stat structure.

       #include <sys/types.h>
       #include <sys/stat.h>
       #include <stdint.h>
       #include <time.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <sys/sysmacros.h>

       main(int argc, char *argv[])
           struct stat sb;

           if (argc != 2) {
               fprintf(stderr, "Usage: %s <pathname>\n", argv[0]);

           if (lstat(argv[1], &sb) == -1) {

           printf("ID of containing device:  [%jx,%jx]\n",
                   (uintmax_t) major(sb.st_dev),
                   (uintmax_t) minor(sb.st_dev));

           printf("File type:                ");

           switch (sb.st_mode & S_IFMT) {
           case S_IFBLK:  printf("block device\n");            break;
           case S_IFCHR:  printf("character device\n");        break;
           case S_IFDIR:  printf("directory\n");               break;
           case S_IFIFO:  printf("FIFO/pipe\n");               break;
           case S_IFLNK:  printf("symlink\n");                 break;
           case S_IFREG:  printf("regular file\n");            break;
           case S_IFSOCK: printf("socket\n");                  break;
           default:       printf("unknown?\n");                break;

           printf("I-node number:            %ju\n", (uintmax_t) sb.st_ino);

           printf("Mode:                     %jo (octal)\n",
                   (uintmax_t) sb.st_mode);

           printf("Link count:               %ju\n", (uintmax_t) sb.st_nlink);
           printf("Ownership:                UID=%ju   GID=%ju\n",
                   (uintmax_t) sb.st_uid, (uintmax_t) sb.st_gid);

           printf("Preferred I/O block size: %jd bytes\n",
                   (intmax_t) sb.st_blksize);
           printf("File size:                %jd bytes\n",
                   (intmax_t) sb.st_size);
           printf("Blocks allocated:         %jd\n",
                   (intmax_t) sb.st_blocks);

           printf("Last status change:       %s", ctime(&sb.st_ctime));
           printf("Last file access:         %s", ctime(&sb.st_atime));
           printf("Last file modification:   %s", ctime(&sb.st_mtime));


       ls(1), stat(1), access(2), chmod(2), chown(2), readlink(2), statx(2),
       utime(2), capabilities(7), inode(7), symlink(7)

       This page is part of release 5.13 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at

Linux                              2021-08-27                            STAT(2)