Ubuntu Manpage: mkdir, mkdirat - create a directory

NAME

       mkdir, mkdirat - create a directory

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #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

       mkdir() attempts to create a directory named path.

       The  argument  mode  specifies  the  mode  for  the  new directory (see inode(7)).  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) for an explanation of the need for mkdirat().

RETURN VALUE

       mkdir()  and mkdirat() return zero on success.  On error, -1 is returned and errno is set to indicate the
       error.

ERRORS

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).)

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)) have not been configured.

VERSIONS

       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

       POSIX.1-2008.

HISTORY

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

       mkdirat()
              Linux 2.6.16, glibc 2.4.

NOTES

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