gfs_rmdir() deletes a directory whose name
is the string specified by gfarm_url. The
directory must be empty.
GFARM_ERR_NO_ERRORThe function terminated successfully.
GFARM_ERR_NO_MEMORYInsufficient memory was available.
GFARM_ERR_PERMISSION_DENIEDgfarm_url
points outside your accessible address space.
GFARM_ERR_DIRECTORY_NOT_EMPTYDirectory is not empty.
GFARM_ERR_NO_SUCH_OBJECTDirectory does not exist.
GFARM_ERR_NOT_A_DIRECTORYA component of the path prefix is not a directory.
An error except the above occurred. The reason is shown by gfarm_error_string(3).