mkdir - make a directory file

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

     int mkdir(const char *path, mode_t mode)

     Mkdir 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; 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 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.  See umask(2).

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

     Mkdir will fail and no directory will be created if:

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

     [ENAMETOOLONG] The path name exceeds PATH_MAX characters.

     [ENOENT]       A component of the path prefix does not exist.

     [EACCES]       Search permission is denied for a component  of  the  path

     [ELOOP]        Too many symbolic links were  encountered  in  translating
                    the pathname.  (Minix-vmd)

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

     [EEXIST]       The named file exists.

     [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 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.

     [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]       Path points outside the process's allocated address space.

     chmod(2), stat(2), umask(2).