ultrix man page for mkdir

mkdir(2)							System Calls Manual							  mkdir(2)

Name
       mkdir - make a directory file

Syntax
       #include <sys/types.h>
       #include <sys/stat.h>

       mkdir(path, mode)
       char *path;
       mode_t mode;

Description
       The  system  call  creates a new directory file with name path.	The mode of the new file is initialized from mode.  The protection part of
       the mode is modified by the process's mode mask.  For further information, see

       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 is created.

       The  low-order  9 bits of mode are modified by the process's file mode creation mask: all bits set in the process's file mode creation mask
       are cleared.  For further information, see

Return Values
       A 0 return value indicates success.  A -1 return value indicates an error, and an error code is stored in errno.

Diagnostics
       The system call fails and a directory is not created if the following occurs:

       [EISDIR]    The named file is a directory, and the arguments specify it is to be opened for writing.

       [ENOTDIR]   A component of the path prefix is not a directory.

       [ENAMETOOLONG]
		   A component of a pathname exceeded 255 characters, or an entire pathname exceeded 1023 characters.

       [ENOENT]    A component of the path prefix does not exist or the path argument points to an empty string and  the  environment  defined	is
		   POSIX or SYSTEM_FIVE.

       [EACCES]    Search  permission  is  denied  for a component of the path prefix, or write permission is denied on the parent directory to be
		   created.

       [EROFS]	   The named file resides on a read-only file system.

       [EEXIST]    The named file exists.

       [EFAULT]    The path points outside the process's allocated address space.

       [ELOOP]	   Too many symbolic links were encountered in translating the pathname.

       [EIO]	   An I/O error occurred while reading from or writing to the file system.

       [EIO]	   An I/O error occurred while making the directory entry or allocating the inode.

       [ENOSPC]    The directory in which the entry for the new directory is being placed cannot be extended, because there is no  space  left	on
		   the file system containing the directory.

       [ENOSPC]    The new directory cannot be created, because there is no space left on the file system that will contain the directory.

       [ENOSPC]    There are no free inodes on the file system on which the directory is being created.

       [EDQUOT]    The	directory  in  which  the entry for the new directory is being placed cannot be extended, because the user's quota of disk
		   blocks on the file system containing the directory has been exhausted.

       [EDQUOT]    The new directory cannot be created, because the user's quota of disk blocks on the file system that will contain 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.

       [ESTALE]    The	file  handle  given  in  the  argument	is invalid.  The file referred to by that file handle no longer exists or has been
		   revoked.

       [ETIMEDOUT] A "connect" request or remote file operation failed because the connected party did not properly respond after a period of time
		   that is dependent on the communications protocol.

       [EMLINK]    The link count of the parent directory would exceed {LINK_MAX}.

See Also
       chmod(2), stat(2), umask(2)

																	  mkdir(2)