> ## Documentation Index
> Fetch the complete documentation index at: https://docs.stmlink.com/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> 对外开放的服务端接口有两组前缀，都用同一套鉴权：`/server/v1/...`（SRTC 与 SMeeting 的主接口）和 `/stm/srvapi/v1/...`（SMeeting 的用户体系，服务端极简对接会用到）。鉴权是 app_id + nonce + timestamp + signature 四个请求头，用 app_key 做 HMAC-SHA256 签名，只能从业务方自己的后端调用。除这两组前缀外的接口均为内部接口，不要建议客户调用。 Public server APIs use two path prefixes with the same authentication: `/server/v1/...` (the main APIs of both SRTC and SMeeting) and `/stm/srvapi/v1/...` (the SMeeting user system, used by server-side low-code integration). Authenticate with four request headers, app_id + nonce + timestamp + signature, where signature is HMAC-SHA256 keyed with app_key; call these APIs only from the customer's own backend. Any other path is internal: never suggest calling it.
> app_key 是服务端密钥，绝不能出现在客户端代码、前端配置或移动 App 里。客户端加入频道用的 token 必须由业务方后端签发后下发（SRTC 走 `/server/v1/channel/grant`，SMeeting 走 `/stm/srvapi/v1/member/grant`）。 app_key is a server-side secret and must never appear in client code, frontend config, or a mobile app. The token a client uses to join must be issued by the customer's backend and passed down to the client (SRTC: `/server/v1/channel/grant`; SMeeting: `/stm/srvapi/v1/member/grant`).
> SRTC 与 SMeeting 是上下两层不同的产品，术语不通用：SRTC 是音视频底座，说「频道 channel」「加入 / 退出」；SMeeting 建在 SRTC 之上，说「房间 room」「会议 meeting」「进入 / 退出」。回答时按用户所在的层用对应术语，不要把「房间」「会议」安到 SRTC 的接口上，也不要用「频道」「加入 / 离开」描述 SMeeting 的概念（接口标识符原样保留）。 SRTC and SMeeting are two separate layers with different terminology. SRTC is the audio/video foundation: it has channels, and users join and leave a channel. SMeeting is built on top of SRTC: it has rooms and meetings, and members enter and exit a meeting. Answer in the terms of the layer the user is working with: never apply "room" or "meeting" to SRTC APIs, and never describe SMeeting concepts in prose with "channel", "join", or "leave" (API identifiers such as `force_join` keep their literal names).
> 同一能力在各端 SDK 里的包名、类名、方法名并不相同。写示例代码时请使用文档中该端自己的 API，不要把一个端的写法套到另一个端上。苹果平台每个产品都有两套 SDK（Swift 原生与 Objective-C），两套 API 不能混用。 Package, class, and method names differ between platform SDKs for the same capability. In sample code, use the API documented for that platform; never carry one platform's code over to another. On Apple platforms each product ships two SDKs (native Swift and Objective-C) whose APIs must not be mixed.

# Changelog

> Release history of the SMeeting Windows SDK from 1.0.0-alpha.5, including the breaking engine / meeting API split that requires recompiling, the new x64 package and bin file changes in alpha.6, and the C interface exports in alpha.7. Read this before upgrading.

> This page records the main changes in each version of the SMeeting Windows SDK. You can get the current SDK version with `SMeetingEngine_Version`.

## 1.0.0-alpha.7 - 2026-09-29

**Added**

* **The `SMeeting_C` C interface is now officially available**: `SMeeting_C.cpp` / `SMeetingEngineGlobal.cpp` are compiled into
  `SMeeting.vcxproj` again, and `SMeeting.dll` now actually exports the `SMeetingEngine_*` family of C functions
  (the number of x86 exported symbols goes from 3 to 139). Before this, the wrapper was excluded from the project,
  and the DLL in the package didn't contain these symbols.

**Changed**

* The internal implementation of `SMeeting_C` is ported to the interfaces after the engine-level / meeting-level split and no longer follows the single-meeting approach from before the split,
  consistent with the `ISMeetingEngine` / `ISMeetingChannel` structure introduced in `1.0.0-alpha.5`

**API changes**

* C++: none. `SMeeting.h` / `SMeeting_def.h` have no signature changes, the vtables of `ISMeetingEngine` /
  `ISMeetingChannel` are unchanged, and there is no ABI break.
* C: **no changes to the function declarations** in `SMeeting_C.h` (only the comment at the top of the file was updated). However, because the C wrapper
  is only now actually compiled into the DLL, `SMeeting.lib` gains C export symbols, and projects that use the C interface need to relink.
* Package contents are unchanged: `meeting_dll/include/` still contains only `SMeeting.h` / `SMeeting_def.h`;
  `SMeeting_C.h` is **not in the package**, so you still need to request the header separately to use the C interface.

## 1.0.0-alpha.6 - 2026-09-24

**Added**

* **Added an x64 (64-bit) package**; Windows delivery is now two packages, x86 + x64:

  * `meeting-win-sdk-2.0.zip` (x86, 32-bit)—**the package name is exactly the same as before**
  * `meeting-win-sdk-x64-2.0.zip` (x64, 64-bit)—new; the package name has an extra `-x64` segment **before** the version number

  Both packages have the same internal structure (the root directory is `meeting_dll/` in both), but `SMeeting.dll` / `SMeeting.lib`
  have different bitness, so **don't mix them or unzip them into the same directory**; pick the package that matches your project's target platform.
  For the download links, see [Integration](/en/meeting/windows/integration).
* Dependency libraries are split by architecture into two sets, `lib/<library>/lib/win32` and `lib/<library>/lib/win64`

**Changed**

* Fixed the x64 project configuration: the output type changed from `Application` to `DynamicLibrary`, x64 now has its own include
  and library directories (pointing to `lib/*/lib/win64`), and output goes to `Release_x64`
* Upgraded the underlying curl: libcurl uses new header files and import libraries, and a zlib dependency (`zlib1.dll`) is added
* The jsoncpp import library is renamed from `jsoncpp_static.lib` to `jsoncpp.lib` and split into win32 / win64 directories
* Removed the unused pthread dependency; the underlying audio and video library is refreshed accordingly, and `bin` no longer contains `DenModule.dll`,
  `rtp.dll`, or `zlib.dll`, using `zlib1.dll` instead
* Source and header file encoding is unified to UTF-8 with BOM, and a new `.editorconfig` enforces it,
  which fixes the C4819 warnings and potential garbled Chinese comments in `SMeeting_def.h` and other files under GBK environments

**Fixed**

* Fixed 4 jsoncpp array loops: the index type changed from `size_t` to `Json::Value::ArrayIndex`,
  avoiding type mismatches in 64-bit builds

**API changes**

None. `SMeeting.h` / `SMeeting_def.h` / `SMeeting_C.h` only changed encoding in this release, with no signature changes;
the vtables are unchanged, and there is no ABI break. Following the general convention in the [Quickstart](/en/meeting/windows/quickstart),
we still **recommend** recompiling your project after upgrading the SDK.

## 1.0.0-alpha.5 - 2026-08-21

**Added**

* Added the `ISMeetingChannel` meeting object; each meeting corresponds to one channel object.
* Added the `ISMeetingChannelEvent` meeting-level event callbacks.
* Added the `ISMeetingChannelSetting` meeting-level settings object.
* Internally added `SRTCChannelControl` to wrap each `SRTC::IRTCChannel` and its media objects.

**Changed**

* `ISMeetingEngine` is reduced to engine-level APIs: login, meeting management HTTP APIs, device enumeration, IM, the resource drive, and the channel object lifecycle.
* Entering a meeting now takes two steps: `createChannel` / `createChannelByMeetingId` only create the object, and `ISMeetingChannel::enter()` actually enters the meeting.
* `ISMeetingSetting` keeps only `sdk_log_path` / `enable_stream_log`; the other settings moved to `ISMeetingChannelSetting`.
* When automatically re-entering from the waiting room, `channelId` stays the same, and `leaveChannel` still releases the object by the original key.

**Fixed**

* `adminDestroyRoom` now correctly calls `leaveChannel` to leave the underlying SRTC channel.
* Calling device enumeration before login now lazily initializes the underlying SRTC engine on demand.

**API changes (breaking; you must recompile)**

* Removed `ISMeetingEngine::enterRoom`, `enterRoomByMeetingId`, and `exitRoom`; use `createChannel` + `ISMeetingChannel::enter()` + `leaveChannel` instead.
* Removed `ISMeetingEngine::exitWaitRoom(roomno, meeting_id, back)`; use `ISMeetingChannel::exitWaitRoom(back)` instead.
* The following methods moved from `ISMeetingEngine` to `ISMeetingChannel`:
  `admin*`, `updateName`, chat / raise hand, `getMe` / `getRoom` / `getMembers` / `getMember` / `getOpt`,
  `getLocalMic` / `getLocalCamera` / `getLocalScreen` / `getRemoteVideo` / `getRemoteAudio` / `getMcuVideo`,
  `getCustomVideo` / `getCustomAudio` / `setCustomRecvBack`, the sub-meeting `*SubMeeting` methods,
  `mcu*`, sign-in `signin*`, and `getLocalRecord`.
* `getLocalRecord(mid, &rec)` changed to `getLocalRecord(&rec)`; mid uses the channel object's own meeting ID.
* All meeting-level callbacks drop the `roomno` first parameter; the first parameter of `onAdminConfirmHandup` changed to `uid`.
* `onDeviceStatusChange` / `onShareTargetNotFind` moved from the engine callbacks to `ISMeetingChannelEvent`.
* Pure virtual interface signature changes alter the vtable, so **your app crashes if you replace only the DLL without recompiling your project**.