关于rt_components_board_init的组件初始化

发布于 2019-11-21 16:18:19 浏览：1724 订阅该版

请教一下，在components.c里的rt_components_board_init函数是如何去执行各个导出标号的函数呀
```void rt_components_board_init(void)
{
#if RT_DEBUG_INIT
    int result;
    const struct rt_init_desc *desc;
    for (desc = &__rt_init_desc_rti_board_start; desc < &__rt_init_desc_rti_board_end; desc ++)
    {
        rt_kprintf("initialize %s", desc->fn_name);
        result = desc->fn();
        rt_kprintf(":%d done<br>", result);
    }
#else
    const init_fn_t *fn_ptr;

for (fn_ptr = &__rt_init_rti_board_start; fn_ptr < &__rt_init_rti_board_end; fn_ptr++)
    {
        (*fn_ptr)();
    }
#endif
}```没有理解&__rt_init_rti_board_start 和&__rt_init_rti_board_end，跳转到定义却又是另一种写法
```static int rti_board_start(void)
{
    return 0;
}
INIT_EXPORT(rti_board_start, "0.end");

static int rti_board_end(void)
{
    return 0;
}
INIT_EXPORT(rti_board_end, "1.end");```
没有理解rti_board_start和rti_board_end 为什么代表这个这个段的开始和结束

CM_USED const init_fn_t __cm_init_##fn SECTION(".rti_fn."level) = fn这种写法到底是吧函数fn放到哪里去了呢，

[indent]```/* board init routines will be called in board_init() function */
#define INIT_BOARD_EXPORT(fn) INIT_EXPORT(fn, "1")

/* pre/device/component/env/app init routines will be called in init_thread */
/* components pre-initialization (pure software initilization) */
#define INIT_PREV_EXPORT(fn) INIT_EXPORT(fn, "2")
/* device initialization */
#define INIT_DEVICE_EXPORT(fn) INIT_EXPORT(fn, "3")
/* components initialization (dfs, lwip, ...) */
#define INIT_COMPONENT_EXPORT(fn) INIT_EXPORT(fn, "4")
/* environment initialization (mount disk, ...) */
#define INIT_ENV_EXPORT(fn) INIT_EXPORT(fn, "5")
/* appliation initialization (rtgui application etc ...) */
#define INIT_APP_EXPORT(fn) INIT_EXPORT(fn, "6")```
[/indent]这些1  2  3  4  5  6的标号到底代表什么意思呢。
先谢谢大家了