Postgis 如何在 Postgres 中存储一个低级类型
How does Postgis store a low-level type in Postgres
PostGIS, what mechanism do they use within Postgres to store the low-level (physical, logical) data type? Is there a mechanism that Postgres exposes whereby a third-party extension may create new native Data Types? I know they have CREATE TYPE SQL 级别，但我一直难以找到它的低级别版本（如果存在）。
It is well documented 如何在 C 中扩展 PostgreSQL 类型系统
PostGIS, what mechanism do they use within Postgres to store the low-level (physical, logical) data type? Is there a mechanism that Postgres exposes whereby a third-party extension may create new native Data Types? I know they have CREATE TYPE SQL 级别，但我一直难以找到它的低级别版本（如果存在）。
It is well documented 如何在 C 中扩展 PostgreSQL 类型系统