PostGIS  2.5.0dev-r@@SVN_REVISION@@
PG_FUNCTION_INFO_V1 ( BOX3D_in  )

BOX3D_in - takes a string rep of BOX3D and returns internal rep.

example: "BOX3D(x1 y1 z1,x2 y2 z2)" or "BOX3D(x1 y1,x2 y2)" z1 and z2 = 0.0