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 *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
       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.  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 pathname did not allow search permission. (See also
path_resolution(7).)

EBADF (mkdirat()) pathname 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 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.

ENOTDIR
(mkdirat()) pathname is relative and dirfd is a file descriptor referring to a file
other than 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.

VERSIONS

       mkdirat() was added in Linux 2.6.16; library support was added in glibc 2.4.

STANDARDS

       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.