mkdir(2) - Linux manual page (original) (raw)

mkdir(2) System Calls Manual mkdir(2)

NAME top

   mkdir, mkdirat - create a directory

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#include <sys/stat.h>**

   **int mkdir(const char ***_path_**, mode_t** _mode_**);**

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

   **int mkdirat(int** _dirfd_**, const char ***_path_**, mode_t** _mode_**);**

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

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

DESCRIPTION top

   **mkdir**() attempts to create a directory named _path_.

   The argument _mode_ specifies the mode for the new directory (see
   [inode(7)](../man7/inode.7.html)).  It is modified by the process's _umask_ in the usual
   way: in the absence of a default ACL, the mode of the created
   directory is (_mode_ & ~_umask_ & 0777).  Whether other _mode_ bits are
   honored for the created directory depends on the operating system.
   For Linux, see VERSIONS below.

   The newly created directory will be owned by the effective user ID
   of the process.  If the directory containing the file has the set-
   group-ID bit set, or if the filesystem is mounted with BSD group
   semantics (_mount -o bsdgroups_ or, synonymously _mount -o grpid_),
   the new directory will inherit the group ownership from its
   parent; otherwise it will be owned by the effective group ID of
   the process.

   If the parent directory has the set-group-ID bit set, then so will
   the newly created directory.

mkdirat() The mkdirat() system call operates in exactly the same way as mkdir(), except for the differences described here.

   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 **mkdir**() 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 **mkdir**()).

   If _path_ is absolute, then _dirfd_ is ignored.

   See [openat(2)](../man2/openat.2.html) for an explanation of the need for **mkdirat**().

RETURN VALUE top

   **mkdir**() and **mkdirat**() return zero on success.  On error, -1 is
   returned and _[errno](../man3/errno.3.html)_ is set to indicate the error.

ERRORS top

   **EACCES** The parent directory does not allow write permission to the
          process, or one of the directories in _path_ did not allow
          search permission.  (See also [path_resolution(7)](../man7/path%5Fresolution.7.html).)

   **EBADF** (**mkdirat**()) _path_ is relative but _dirfd_ is neither **AT_FDCWD**
          nor a valid file descriptor.

   **EDQUOT** The user's quota of disk blocks or inodes on the filesystem
          has been exhausted.

   **EEXIST** _path_ already exists (not necessarily as a directory).  This
          includes the case where _path_ is a symbolic link, dangling
          or not.

   **EFAULT** _path_ points outside your accessible address space.

   **EINVAL** The final component ("basename") of the new directory's
          _path_ is invalid (e.g., it contains characters not permitted
          by the underlying filesystem).

   **ELOOP** Too many symbolic links were encountered in resolving _path_.

   **EMLINK** The number of links to the parent directory would exceed
          **LINK_MAX**.

   **ENAMETOOLONG**
          _path_ was too long.

   **ENOENT** A directory component in _path_ does not exist or is a
          dangling symbolic link.

   **ENOMEM** Insufficient kernel memory was available.

   **ENOSPC** The device containing _path_ has no room for the new
          directory.

   **ENOSPC** The new directory cannot be created because the user's disk
          quota is exhausted.

   **ENOTDIR**
          A component used as a directory in _path_ is not, in fact, a
          directory.

   **ENOTDIR**
          (**mkdirat**()) _path_ is relative and _dirfd_ is a file descriptor
          referring to a file other than a directory.

   **EPERM** The filesystem containing _path_ does not support the
          creation of directories.

   **EROFS** _path_ refers to a file on a read-only filesystem.

   **EOVERFLOW**
          UID or GID mappings (see [user_namespaces(7)](../man7/user%5Fnamespaces.7.html)) have not been
          configured.

VERSIONS top

   Under Linux, apart from the permission bits, the **S_ISVTX** _mode_ bit
   is also honored.

glibc notes On older kernels where mkdirat() is unavailable, the glibc wrapper function falls back to the use of mkdir(). When path is relative, glibc constructs a pathname based on the symbolic link in /proc/self/fd that corresponds to the dirfd argument.

STANDARDS top

   POSIX.1-2008.

HISTORY top

   **mkdir**()
          SVr4, BSD, POSIX.1-2001.

   **mkdirat**()
          Linux 2.6.16, glibc 2.4.

NOTES top

   There are many infelicities in the protocol underlying NFS.  Some
   of these affect **mkdir**().

SEE ALSO top

   [mkdir(1)](../man1/mkdir.1.html), [chmod(2)](../man2/chmod.2.html), [chown(2)](../man2/chown.2.html), [mknod(2)](../man2/mknod.2.html), [mount(2)](../man2/mount.2.html), [rmdir(2)](../man2/rmdir.2.html),
   [stat(2)](../man2/stat.2.html), [umask(2)](../man2/umask.2.html), [unlink(2)](../man2/unlink.2.html), [acl(5)](../man5/acl.5.html), [path_resolution(7)](../man7/path%5Fresolution.7.html)

COLOPHON top

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Linux man-pages 6.15 2025-05-17 mkdir(2)

Pages that refer to this page:mkdir(1), chmod(2), chown(2), fanotify_mark(2), F_NOTIFY(2const), io_uring_enter2(2), io_uring_enter(2), mknod(2), open(2), rmdir(2), seccomp_unotify(2), syscalls(2), umask(2), io_uring_prep_mkdir(3), io_uring_prep_mkdirat(3), mkdtemp(3), mode_t(3type), proc_pid_attr(5), cpuset(7), inotify(7), signal-safety(7), mount(8)