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

NAME
       mkdir, mkdirat - create a directory

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

       int mkdir(const char *pathname, mode_t mode);

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

       int mkdirat(int dirfd, const char *pathname, 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 pathname.

       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 NOTES 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 dif-
       ferences described here.

       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 mkdir() for a relative pathname).

       If pathname is relative and dirfd is the special value AT_FDCWD, then pathname  is  inter-
       preted relative to the current working directory of the calling process (like mkdir()).

       If pathname 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, or -1 if an error occurred (in which case,
       errno is set appropriately).

ERRORS
       EACCES The parent directory does not allow write permission to the process, or one of  the
              directories  in  pathname  did not allow search permission.  (See also path_resolu-
              tion(7).)

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

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

       EFAULT pathname points outside your accessible address space.

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

       ELOOP  Too many symbolic links were encountered in resolving pathname.

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

       ENAMETOOLONG
              pathname was too long.

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

       ENOMEM Insufficient kernel memory was available.

       ENOSPC The device containing pathname 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 pathname is not, in fact, a directory.

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

       EROFS  pathname refers to a file on a read-only filesystem.

       The following additional errors can occur for mkdirat():

       EBADF  dirfd is not a valid file descriptor.

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

VERSIONS
       mkdirat()  was added to Linux in kernel 2.6.16; library support was added to glibc in ver-
       sion 2.4.

CONFORMING TO
       mkdir(): SVr4, BSD, POSIX.1-2001, POSIX.1-2008.

       mkdirat(): POSIX.1-2008.

NOTES
       Under Linux, apart from the permission bits, the S_ISVTX mode bit is also honored.

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

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

SEE ALSO
       mkdir(1), chmod(2), chown(2), mknod(2), mount(2), rmdir(2), stat(2), umask(2),  unlink(2),
       acl(5) path_resolution(7)

COLOPHON
       This  page  is  part of release 4.15 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 https://www.kernel.org/doc/man-pages/.

Linux                                       2017-09-15                                   MKDIR(2)