Section: Linux Programmer's Manual (2)
mkdir, mkdirat - create a directory
int mkdir(const char *pathname, mode_t mode);
#include <fcntl.h> /* Definition of AT_* constants */
int mkdirat(int dirfd, const char *pathname, mode_t mode);
Feature Test Macro Requirements for glibc (see
- Since glibc 2.10:
_POSIX_C_SOURCE >= 200809L
- Before glibc 2.10:
attempts to create a directory named
specifies the mode for the new directory (see
It is modified by the process's
in the usual way: in the absence of a default ACL, the mode of the
created directory is
(mode & ~umask & 0777).
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
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
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.
system call operates in exactly the same way as
except for the differences described here.
If the pathname given in
is relative, then it is interpreted relative to the directory
referred to by the file descriptor
(rather than relative to the current working directory of
the calling process, as is done by
for a relative pathname).
is relative and
is the special value
is interpreted relative to the current working
directory of the calling process (like
is absolute, then
for an explanation of the need for
return zero on success, or -1 if an error occurred (in which case,
is set appropriately).
The parent directory does not allow write permission to the process,
or one of the directories in
did not allow search permission.
The user's quota of disk blocks or inodes on the filesystem has been
already exists (not necessarily as a directory).
This includes the case where
is a symbolic link, dangling or not.
pathname points outside your accessible address space.
The final component ("basename") of the new directory's
(e.g., it contains characters not permitted by the underlying filesystem).
Too many symbolic links were encountered in resolving
The number of links to the parent directory would exceed
pathname was too long.
A directory component in
does not exist or is a dangling symbolic link.
Insufficient kernel memory was available.
The device containing
has no room for the new directory.
The new directory cannot be created because the user's disk quota is
A component used as a directory in
is not, in fact, a directory.
The filesystem containing
does not support the creation of directories.
refers to a file on a read-only filesystem.
The following additional errors can occur for
is not a valid file descriptor.
is relative and
is a file descriptor referring to a file other than a directory.
was added to Linux in kernel 2.6.16;
library support was added to glibc in version 2.4.
SVr4, BSD, POSIX.1-2001, POSIX.1-2008.
Under Linux, apart from the permission bits, the
bit is also honored.
There are many infelicities in the protocol underlying NFS.
Some of these affect
On older kernels where
is unavailable, the glibc wrapper function falls back to the use of
is a relative pathname,
glibc constructs a pathname based on the symbolic link in
that corresponds to the
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