Ubuntu Manpage: mkdir, mkdirat - create a directory

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:
               _XOPEN_SOURCE >= 700 || _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 stat(2)).  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 differences
       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 interpreted 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_resolution(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.

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 version 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.

COLOPHON

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