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

       stat, fstat, lstat, fstatat - get file status

       #include <sys/types.h>
       #include <sys/stat.h>
       #include <unistd.h>

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

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

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

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

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

           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

       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 infor-
       mation 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 archi-
       tectures.  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)  repre-

              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 byte.

              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 de-
              fault, 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 appropriately.

       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.

       EFAULT Bad address.

       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 flags.

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

              A component of the path prefix of pathname is not 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.

       The following additional errors can occur for fstatat():

       EBADF  dirfd is not a valid file descriptor.

       EINVAL Invalid flag specified in flags.

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

       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 precision.

       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 suit-
       able feature test macros are defined.  Nanosecond timestamps were stan-
       dardized in POSIX.1-2008, and, starting with version  2.12,  glibc  ex-
       poses 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 de-
       fined, then the nanosecond values are exposed with names  of  the  form

   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 pad-

       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 ac-
              commodate 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  applica-
       tions,  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 <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:  [%lx,%lx]\n",
                (long) major(sb.st_dev), (long) 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:            %ld\n", (long) sb.st_ino);

           printf("Mode:                     %lo (octal)\n",
                   (unsigned long) sb.st_mode);

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

           printf("Preferred I/O block size: %ld bytes\n",
                   (long) sb.st_blksize);
           printf("File size:                %lld bytes\n",
                   (long long) sb.st_size);
           printf("Blocks allocated:         %lld\n",
                   (long long) 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 5.07 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                             2020-04-11                           STAT(2)

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