stat(2)                       System Calls Manual                      stat(2)

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

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <sys/stat.h>

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

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

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

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

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

       fstatat():
           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:
               _ATFILE_SOURCE

DESCRIPTION
       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 path that lead to the file.

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

       lstat() is identical to stat(), except that if path 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 (see stat(3type)).

       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.

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

       If path is absolute, then dirfd is ignored.

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

       AT_EMPTY_PATH (since Linux 2.6.39)
              If path is an empty string (or NULL, since Linux 6.11) 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 path.
              Since Linux 3.1 this flag is ignored.  Since Linux 4.11 this
              flag is implied.

       AT_SYMLINK_NOFOLLOW
              If path 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().

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

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

       EBADF  fd is not a valid open file descriptor.

       EBADF  (fstatat()) path 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.

       ENAMETOOLONG
              path is too long.

       ENOENT A component of path does not exist or is a dangling symbolic
              link.

       ENOENT path is an empty string and AT_EMPTY_PATH was not specified in
              flags.

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

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

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

       EOVERFLOW
              path 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.

STANDARDS
       POSIX.1-2008.

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

       fstatat()
              POSIX.1-2008.  Linux 2.6.16, glibc 2.4.

       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.)

   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:

       __old_kernel_stat
              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 binaries.

       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,
       newfstatat().

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

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

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

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

           if (lstat(argv[1], &sb) == -1) {
               perror("lstat");
               exit(EXIT_FAILURE);
           }

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

           exit(EXIT_SUCCESS);
       }

SEE ALSO
       ls(1), stat(1), access(2), chmod(2), chown(2), readlink(2), statx(2),
       utime(2), stat(3type), capabilities(7), inode(7), symlink(7)

Linux man-pages 6.14              2025-05-06                           stat(2)