mkdir - make a directory
int mkdir(const char *path, mode_t mode);
The mkdir() function creates a new directory named by the
path name pointed to by path. The mode of the new directory
is initialized from mode (see chmod(2) for values of mode).
The protection part of the mode argument is modified by the
process's file creation mask (see umask(2)).
The directory's owner ID is set to the process's effective
user ID. The directory's group ID is set to the process's
effective group ID, or if the S_ISGID bit is set in the
parent directory, then the group ID of the directory is
inherited from the parent. The S_ISGID bit of the new
directory is inherited from the parent directory.
If path is a symbolic link, it is not followed.
The newly created directory is empty with the exception of
entries for itself (.) and its parent directory (..).
Upon successful completion, mkdir() marks for update the
st_atime, st_ctime and st_mtime fields of the directory.
Also, the st_ctime and st_mtime fields of the directory that
contains the new entry are marked for update.
Upon successful completion, 0 is returned. Otherwise, -1 is
returned, no directory is created, and errno is set to
indicate the error.
The mkdir() function will fail if:
Either a component of the path prefix denies search
permission or write permission is denied on the parent
directory of the directory to be created.
The directory where the new file entry is being placed
cannot be extended because the user's quota of disk
blocks on that file system has been exhausted; the new
directory cannot be created because the user's quota
of disk blocks on that file system has been exhausted;
or the user's quota of inodes on the file system where
the file is being created has been exhausted.
The named file already exists.
The path argument points to an illegal address.
An attempt was made to create an extended attribute
that is a directory.
EIO An I/O error has occurred while accessing the file
ELOOP Too many symbolic links were encountered in translat-
The maximum number of links to the parent directory
would be exceeded.
The length of the path argument exceeds PATH_MAX, or
the length of a path component exceeds NAME_MAX while
_POSIX_NO_TRUNC is in effect.
A component of the path prefix does not exist or is a
The path argument points to a remote machine and the
link to that machine is no longer active.
No free space is available on the device containing
A component of the path prefix is not a directory.
EROFS The path prefix resides on a read-only file system.
When a UFS file system is mounted with logging enabled, file
system transactions that free blocks from files might not
actually add those freed blocks to the file system's free
list until some unspecified time in the future. This
behavior improves file system performance but does not con-
form to the POSIX, Single UNIX Specification, SPARC
Conformance Definition, System V Application Binary Inter-
face, System V Interface Definition, and X/Open Portability
Guide Standards, which require that freed space be available
immediately. To enable standards conformance regarding file
deletions or to address the problem of not being able to
grow files on a relatively full UFS file system even after
files have been deleted, disable UFS logging (see
See attributes(5) for descriptions of the following attri-
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| Interface Stability | Standard |
| MT-Level | Async-Signal-Safe |
mount_ufs(1M), chmod(2), mknod(2), umask(2), stat(3HEAD),
Man(1) output converted with