int _START_SHAPE_TEST_SURROUNDING_COORDS(Vector3* pVec1, Vector3* pVec2, int flag, Entity entity, int flag2);
Since it is only used in the PC version, likely some mouse-friendly shape test. Uses in vector arguments.
it returns a ShapeTest handle that can be used with GET_SHAPE_TEST_RESULT.
In its only usage in game scripts its called with flag set to 511, entity to player_ped_id and flag2 set to 7
START_SHAPE_TEST_LOS_PROBE for flags.