> For the complete documentation index, see [llms.txt](https://docs.postgresql.tw/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.postgresql.tw/server-programming/archive-modules/archive-module-init.md).

# 49.1. Initialization Functions \#

An archive library is loaded by dynamically loading a shared library with the [archive\_library](/server-administration/runtime-config/runtime-config-wal.md#GUC-ARCHIVE-LIBRARY)'s name as the library base name. The normal library search path is used to locate the library. To provide the required archive module callbacks and to indicate that the library is actually an archive module, it needs to provide a function named `_PG_archive_module_init`. The result of the function must be a pointer to a struct of type `ArchiveModuleCallbacks`, which contains everything that the core code needs to know to make use of the archive module. The return value needs to be of server lifetime, which is typically achieved by defining it as a `static const` variable in global scope.

```

typedef struct ArchiveModuleCallbacks
{
    ArchiveStartupCB startup_cb;
    ArchiveCheckConfiguredCB check_configured_cb;
    ArchiveFileCB archive_file_cb;
    ArchiveShutdownCB shutdown_cb;
} ArchiveModuleCallbacks;
typedef const ArchiveModuleCallbacks *(*ArchiveModuleInit) (void);
```

Only the `archive_file_cb` callback is required. The others are optional.

***

原文：[PostgreSQL 18.6 Documentation](https://www.postgresql.org/docs/18/archive-module-init.html)（英文原文，待翻譯）


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.postgresql.tw/server-programming/archive-modules/archive-module-init.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.