谁来给我详细解释下“注册孔定位的用户函数”每一句代码啊，非常感谢啊！

sys601

/*注册孔定位的用户函数*/
int rpo_routine_hole(tag_t obj_id)
{
int irc;
uf_list_p_t edge_list;
tag_t obj_id_target[1],obj_id_tool[1];
char *constraint_value[]={"0.0"};
, o& N& B3 n# a4 b4 vchar *constraint_array[]={"PARA_DIST_PARMS"};
int target_qualifier[]={UF_MODL_ARC_CENTER};
4 Y3 o, r2 I, F: Rint tool_qualifier[]={UF_MODL_ARC_CENTER};
# h( J( v5 K4 D4 sUF_MODL_ask_feat_edges(obj_id, &edge_list );
% w+ H3 Y$ E# C; J7 pUF_MODL_ask_list_item(edge_list, 0, &obj_id_tool[0]);
4 L4 U4 n* }" i; V- ~  _UF_MODL_delete_list(&edge_list);
obj_id_target[0] = target_edge;
irc=UF_MODL_create_rpo_constraints(obj_id,NULL_TAG,NULL_TAG,obj_id_target,
( z2 j% n7 r: {  Ltarget_qualifier,obj_id_tool,tool_qualifier,constraint_value,constraint_array,1);
return irc;
* J. z* b. f) B}