MKDIR(2) BSD System Calls Manual MKDIR(2)NAME
mkdir, mkdirat — make a directory file
Standard C Library (libc, -lc)
mkdir(const char *path, mode_t mode);
mkdirat(int fd, const char *path, mode_t mode);
The directory path is created with the access permissions specified by
mode and restricted by the umask(2) of the calling process.
The directory's owner ID is set to the process's effective user ID. The
directory's group ID is set to that of the parent directory in which it
The mkdirat() system call is equivalent to mkdir() except in the case
where path specifies a relative path. In this case the newly created
directory is created relative to the directory associated with the file
descriptor fd instead of the current working directory. If mkdirat() is
passed the special value AT_FDCWD in the fd parameter, the current work‐
ing directory is used and the behavior is identical to a call to mkdir().
The mkdir() function returns the value 0 if successful; otherwise the
value -1 is returned and the global variable errno is set to indicate the
The mkdir() system call will fail and no directory will be created if:
[ENOTDIR] A component of the path prefix is not a directory.
[ENAMETOOLONG] A component of a pathname exceeded 255 characters, or
an entire path name exceeded 1023 characters.
[ENOENT] A component of the path prefix does not exist.
[EACCES] Search permission is denied for a component of the
path prefix, or write permission is denied on the par‐
ent directory of the directory to be created.
[ELOOP] Too many symbolic links were encountered in translat‐
ing the pathname.
[EPERM] The parent directory of the directory to be created
has its immutable flag set, see the chflags(2) manual
page for more information.
[EROFS] The named directory would reside on a read-only file
[EMLINK] The new directory cannot be created because the parent
directory contains too many subdirectories.
[EEXIST] The named file exists.
[ENOSPC] The new directory cannot be created because there is
no space left on the file system that will contain the
[ENOSPC] There are no free inodes on the file system on which
the directory is being created.
[EDQUOT] The new directory cannot be created because the user's
quota of disk blocks on the file system that will con‐
tain the directory has been exhausted.
[EDQUOT] The user's quota of inodes on the file system on which
the directory is being created has been exhausted.
[EIO] An I/O error occurred while making the directory entry
or allocating the inode.
[EIO] An I/O error occurred while reading from or writing to
the file system.
[EFAULT] The path argument points outside the process's allo‐
cated address space.
In addition to the errors returned by the mkdir(), the mkdirat() may fail
[EBADF] The path argument does not specify an absolute path
and the fd argument is neither AT_FDCWD nor a valid
file descriptor open for searching.
[ENOTDIR] The path argument is not an absolute path and fd is
neither AT_FDCWD nor a file descriptor associated with
SEE ALSOchflags(2), chmod(2), stat(2), umask(2)STANDARDS
The mkdir() system call is expected to conform to ISO/IEC 9945-1:1990
(“POSIX.1”). The mkdirat() system call follows The Open Group Extended
API Set 2 specification.
The mkdirat() system call appeared in FreeBSD 8.0.
BSD June 26, 2008 BSD