From 52cd71ddc7e8a9ddbde3ca5f9c07a132ac599214 Mon Sep 17 00:00:00 2001
From: huanghf <huanghaifei3@h-partners.com>
Date: Thu, 3 Jul 2025 14:14:10 +0800
Subject: [PATCH] update doc

Signed-off-by: huanghf <huanghaifei3@h-partners.com>
---
 .../ffrt/ffrt-api-guideline-c.md              | 58 ++++++++++++++++++
 .../ffrt/ffrt-api-guideline-c.md              | 59 +++++++++++++++++++
 2 files changed, 117 insertions(+)

diff --git a/en/application-dev/ffrt/ffrt-api-guideline-c.md b/en/application-dev/ffrt/ffrt-api-guideline-c.md
index 11a4639bf85..1b5640373da 100644
--- a/en/application-dev/ffrt/ffrt-api-guideline-c.md
+++ b/en/application-dev/ffrt/ffrt-api-guideline-c.md
@@ -2361,3 +2361,61 @@ Description
         return 0;
     }
     ```
+
+## Fiber process
+
+### ffrt_fiber_t
+
+#### Declaration
+
+```c
+struct ffrt_fiber_t;
+```
+
+#### Description
+
+`ffrt_fiber_t` is a fiber storage entity type used to store and restore execution context.
+
+#### Method
+
+##### ffrt_fiber_init
+
+Declaration
+
+```c
+FFRT_C_API int ffrt_fiber_init(ffrt_fiber_t* fiber, void(*func)(void*), void* arg, void* stack, size_t stack_size);
+```
+
+Parameters
+
+- `fiber`: Fiber pointer.
+- `func`: The function pointer entry at fiber startup.
+- `arg`: Function parameter at fiber startup.
+- `stack`: The starting address of the stack space used by the fiber during runtime.
+- `stack_size`: The size of the fiber stack, measured in bytes.
+
+Return Values
+
+- Initialize successfully and return `ffrt_success`; otherwise, return `ffrt_error`. The common reason is that the `stack_size` does not meet the minimum stack space limit, which varies across platforms. It is recommended to set a stack space of 4KB or more.
+
+Description
+
+- This function initializes the fiber by passing the function pointer, parameters for starting the fiber, and the runtime stack space. The caller manages the fiber stack's lifecycle.
+
+##### ffrt_fiber_switch
+
+Declaration
+
+```c
+FFRT_C_API void ffrt_fiber_switch(ffrt_fiber_t* from, ffrt_fiber_t* to);
+```
+
+Parameters
+
+- `from`: The thread calling this function will pause the execution of the current task and save the current context to the fiber pointed to by `from`.
+- `to`: Restore the fiber pointed to by `to` to the current context, and the thread calling this function will execute the task corresponding to `to`.
+
+Description
+
+- Switching the fiber context, the thread calling this function will pause the execution of the current task, save the current context to the fiber pointed to by `from`, and restore the fiber pointed to by `to` to the current context, executing the task corresponding to `to`.
+- Note: This interface cannot determine the validity of `from` and `to`. The caller needs to verify the address validity themselves, otherwise it will cause the process to crash.
diff --git a/zh-cn/application-dev/ffrt/ffrt-api-guideline-c.md b/zh-cn/application-dev/ffrt/ffrt-api-guideline-c.md
index 41b4ba82fa9..2de3fc883e2 100644
--- a/zh-cn/application-dev/ffrt/ffrt-api-guideline-c.md
+++ b/zh-cn/application-dev/ffrt/ffrt-api-guideline-c.md
@@ -2360,3 +2360,62 @@ FFRT_C_API int ffrt_loop_timer_stop(ffrt_loop_t loop, ffrt_timer_t handle);
         return 0;
     }
     ```
+
+## 纤程
+
+### ffrt_fiber_t
+
+#### 声明
+
+```c
+struct ffrt_fiber_t;
+```
+
+#### 描述
+
+- 纤程是一种轻量级的用户态线程，用于在用户空间内实现高效的任务调度和上下文切换。
+- `ffrt_fiber_t`为纤程存储实体类型，用于保存和恢复执行上下文。
+
+#### 方法
+
+##### ffrt_fiber_init
+
+声明
+
+```c
+FFRT_C_API int ffrt_fiber_init(ffrt_fiber_t* fiber, void(*func)(void*), void* arg, void* stack, size_t stack_size);
+```
+
+参数
+
+- `fiber`：纤程指针。
+- `func`：纤程启动时的函数指针入口。
+- `arg`：纤程启动时的函数入参。
+- `stack`：纤程运行时使用的栈空间起始地址。
+- `stack_size`：纤程栈大小，单位为字节。
+
+返回值
+
+- 初始化成功返回`ffrt_success`，否则返回`ffrt_error`。返回错误的常见原因是`stack_size`不满足最小栈空间限制（不同平台存在差异），建议设置栈空间大小为4KB或以上。
+
+描述
+
+- 该函数用于初始化纤程，需要传入启动纤程的函数指针和入参，以及运行时使用的栈空间，纤程不管理任何的内存，栈的生命周期由调用方管理。
+
+##### ffrt_fiber_switch
+
+声明
+
+```c
+FFRT_C_API void ffrt_fiber_switch(ffrt_fiber_t* from, ffrt_fiber_t* to);
+```
+
+参数
+
+- `from`：调用该函数的线程会暂停当前任务的执行，并保存当前上下文到`from`指向的纤程。
+- `to`：将`to`指向的纤程恢复到当前上下文，调用该函数的线程将执行`to`对应的任务。
+
+描述
+
+- 切换纤程上下文时，调用该函数的线程会暂停当前任务，保存上下文到`from`纤程，并恢复`to`纤程上下文，执行`to`对应的任务。
+- 注意：本接口不校验对`from`、`to`的有效性，调用方需自行校验地址有效性，否则会导致该进程崩溃。
-- 
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