> ## 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.

# IRTCEngine

> API reference for IRTCEngine, the process-level object of the Windows SRTC C++ SDK: RTCEngine_Init / RTCEngine_Free, version and error messages, creating and leaving channels, network speed tests, device enumeration, and log upload. Read when setting up the engine or managing channels.

## IRTCEngine

### Create IRTCEngine

```cpp theme={null}
RTCENGINE_API StatusCode RTCENGINE_CALL RTCEngine_Init(IRTCEngine** rtc, RTCEngineOptions* opt);
```

**Parameters**

| rtc | The IRTCEngine object; nullptr on failure |
| - | - |
| opt | Engine initialization options, [RTCEngineOptions](/en/rtc/windows/types#engine-initialization-options-rtcengineoptions). **Passing nullptr writes no SDK log at all** |

Note: the log switch and log path used to be on `IRTCSetting` (`enable_stream_log` / `sdk_log_path`) and have moved here—
they're consumed while the engine itself initializes, before any channel object exists.

### Release IRTCEngine

```cpp theme={null}
RTCENGINE_API void RTCENGINE_CALL RTCEngine_Free(IRTCEngine** rtc);
```

**Parameters**

| rtc | The IRTCEngine object |
| - | - |

### Get the version number

```cpp theme={null}
RTCENGINE_API StatusCode RTCENGINE_CALL RTCEngine_Version(const char*v1);
```

**Parameters**

| v1 | SDK version number |
| - | - |

Note: the caller must allocate the memory before passing it in, at least 100 bytes.

### Get the error code description

```cpp theme={null}
RTCENGINE_API void RTCENGINE_CALL RTCEngine_GetStatusMsg(StatusCode code, char* msg);
```

**Parameters**

| code | Error code |
| - | - |
| msg | Error code description |

Note: the caller must allocate the memory for msg before passing it in, at least 100 bytes. The text is GBK-encoded Chinese.

## Basic functions

### Set the event handler

```cpp theme={null}
virtual StatusCode setEventHandler(IRTCEngineEvent* e) = 0;
```

**Parameters**

| e | An implementation of the pure virtual event callback class; for the callbacks, see [IRTCEngineEvent](/en/rtc/windows/api-reference/IRTCEngineEvent) |
| - | - |

## Channel functions

You can join multiple channels at the same time. Each channel corresponds to an [IRTCChannel](/en/rtc/windows/api-reference/IRTCChannel) object, and channel-level methods and callbacks are all on that object,
instead of being distinguished by a leading `channelId` parameter on `IRTCEngine` as in older versions.

**About channelId**

* `channelId` is the value of the `channel` field in the token. The SDK parses it internally, and you get it through `IRTCChannel::getChannelId()`
* `channelId` is used only by `leaveChannel` and `getChannelIds`; all other methods are called directly on the channel object

### Create a channel object

```cpp theme={null}
virtual StatusCode createChannel(const char* token, IRTCChannel** ch) = 0;
```

**Parameters**

| token | The token required to join the channel |
| - | - |
| ch | Output parameter, the channel object. nullptr on failure |

Note: this **only creates the object and doesn't join the channel**. After you get the object, set up its configuration and event handler, then call [IRTCChannel::join()](/en/rtc/windows/api-reference/IRTCChannel#join-the-channel).
Creating the same channel again returns `Conflict`; if no channel can be parsed from the token, it returns `SdkTokenInvalid`.

### Leave a channel

```cpp theme={null}
virtual void leaveChannel(const char* channelId) = 0;
```

**Parameters**

| channelId | ID of the channel to leave |
| - | - |

### Leave all channels

```cpp theme={null}
virtual void leaveAllChannel() = 0;
```

### Get the list of joined channels

```cpp theme={null}
virtual StatusCode getChannelIds(char** s, int* c) = 0;
```

**Parameters**

| s | JSON array of joined channelIds, for example \["ch\_a","ch\_b"] |
| - | - |
| c | Length of the JSON array |

## Media streaming functions

### Network speed test

```cpp theme={null}
	virtual StatusCode probeNetwork(int time, int upindex, int downindex) = 0;
```

**Parameters**

| time | Duration of the speed test; a multiple of 10 is recommended |
| - | - |
| upindex | Uplink test amount (in KB); 0 skips the uplink test |
| downindex | Downlink test amount (in KB); 0 skips the downlink test |

Note: the test results are returned in the [callback](/en/rtc/windows/api-reference/IRTCEngineEvent#network-probe-result-callback).

### Get camera info

```cpp theme={null}
virtual StatusCode getEnumVideo(char** devices, int* iSize) = 0;
```

**Parameters**

| Devices | Camera info JSON, see [Camera enumeration info](/en/rtc/windows/types#camera-enumeration-info) |
| - | - |
| iSize | Length of the camera info JSON |

### Get screen info

```cpp theme={null}
virtual StatusCode getEnumScreen(char** devices, int* iSize) = 0;
```

**Parameters**

| Devices | Screen info JSON, see [Shared screen enumeration info](/en/rtc/windows/types#shared-screen-enumeration-info) |
| - | - |
| iSize | Length of the screen info JSON |

### Get microphone info

```cpp theme={null}
virtual StatusCode getEnumAudio(char** devices, int* iSize) = 0;
```

**Parameters**

| Devices | Microphone info JSON, see [Microphone info](/en/rtc/windows/types#microphone/speaker-enumeration-info) |
| - | - |
| iSize | Length of the microphone info JSON |

### Get speaker info

```cpp theme={null}
virtual StatusCode getEnumSpeaker(char** devices, int* iSize) = 0;
```

**Parameters**

| Devices | Speaker info JSON, see [Speaker info](/en/rtc/windows/types#microphone/speaker-enumeration-info) |
| - | - |
| iSize | Length of the speaker info JSON |

## Other

### Add a log to upload

```cpp theme={null}
virtual StatusCode addUploadLog(const char* type ,const char* msg) = 0;
```

**Parameters**

| type | Log type identifier |
| - | - |
| msg | Log content |

Logs you add are uploaded to the log server.