PK_SHELL_ask_acorn_vertex

PK_ERROR_code_t    PK_SHELL_ask_acorn_vertex
(
--- received arguments ---
PK_SHELL_t         shell,       --- a shell

--- returned arguments ---
PK_VERTEX_t *const vertex       --- its acorn vertex (or PK_ENTITY_null)
)


This function returns the single acorn vertex of the given shell if the shell
is of type PK_SHELL_type_acorn_c, otherwise PK_ENTITY_null is returned.