> ## 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.

# Error codes

> RTCEngineError values for the iOS (Objective-C) SRTC SDK, grouped into system (100001–100004), common (100005–100008), network (100009–100011), and client (103001–103004) errors. Read when handling or logging errors from iOS SDK callbacks.

### RTCEngineError

Error codes

| **Enum name** | **Value** | **Description** |
| - | :-: | - |
| RTCEngineErrorOK | `0` | No error |
| **System errors** | | |
| RTCEngineErrorSystemError | `100001` | Internal system error |
| RTCEngineErrorNotInitialized | `100002` | Not initialized |
| RTCEngineErrorMediaNotInitialized | `100003` | The media module isn't initialized yet |
| RTCEngineErrorProtocolParsingError | `100004` | Protocol parsing error |
| **Common errors** | | |
| RTCEngineErrorTimeout | `100005` | Timed out |
| RTCEngineErrorInvalidArgs | `100006` | Invalid arguments |
| RTCEngineErrorConflict | `100007` | Conflict from a repeated operation |
| RTCEngineErrorSdkTokenInvalid | `100008` | The SDK token is invalid |
| **Network errors** | | |
| RTCEngineErrorNetError | `100009` | Network error |
| RTCEngineErrorMediaNetError | `100010` | Media network error |
| RTCEngineErrorNotFound | `100011` | Target doesn't exist |
| **Client errors** | | |
| RTCEngineErrorDeviceNoAuthorized | `103001` | No permission to access the device |
| RTCEngineErrorNotJoinedChannel | `103002` | Not in the channel |
| RTCEngineErrorForbidden | `103003` | Operation not allowed |
| RTCEngineErrorStreamNotFound | `103004` | Stream doesn't exist |