list_fd是干啥用的？

发布于 2022-10-28 18:04:36 浏览：880 订阅该版

aozima 2022-10-28

调网络不抓包，调I2C等时序不上逻辑分析仪，就像电工不用万用表！多用整理的好的文字，比截图更省流量，还能在整理过程中思考。

用户名由3_15位 2022-10-31

这家伙很懒，什么也没写！

用户名由3_15位 2022-10-31

这家伙很懒，什么也没写！

我照着改了一下代码,不过我打印出来永远都是空的。不知道这个函数声明用途。
你看一下有没有什么问题？没有我提交一个pr上去

![709.png](https://oss-club.rt-thread.org/uploads/20221031/62999c7e8d682cd38dc434cd5fd88627.png)

```c
int list_fd(void)
{
    int index;
    struct dfs_fdtable *fd_table;

char *buff = rt_malloc(1024);
    char *buff_start = buff;

fd_table = dfs_fdtable_get();
    if (!fd_table) return -1;

rt_enter_critical();
    buff += rt_sprintf(buff, "fd type    ref magic  path\n");
    buff += rt_sprintf(buff, "-- ------  --- ----- ------\n");
    for (index = 0; index < (int)fd_table->maxfd; index ++)
    {
        struct dfs_fd *fd = fd_table->fds[index];

if (fd && fd->fops)
        {
            buff += rt_sprintf(buff,"%2d ", index + DFS_FD_OFFSET);
            if (fd->type == FT_DIRECTORY)    buff += rt_sprintf(buff,"%-7.7s ", "dir");
            else if (fd->type == FT_REGULAR) buff += rt_sprintf(buff,"%-7.7s ", "file");
            else if (fd->type == FT_SOCKET)  buff += rt_sprintf(buff,"%-7.7s ", "socket");
            else if (fd->type == FT_USER)    buff += rt_sprintf(buff,"%-7.7s ", "user");
            else if (fd->type == FT_DEVICE)   buff += rt_sprintf(buff,"%-7.7s ", "device");
            else rt_kprintf("%-8.8s ", "unknown");
            buff += rt_sprintf(buff,"%3d ", fd->ref_count);
            buff += rt_sprintf(buff,"%04x  ", fd->magic);
            if (fd->fs && fd->fs->path && rt_strlen(fd->fs->path) > 1)
            {
                buff += rt_sprintf(buff,"%s", fd->fs->path);
            }
            if (fd->path)
            {
                buff += rt_sprintf(buff,"%s\n", fd->path);
            }
            else
            {
                buff += rt_sprintf(buff,"\n");
            }
        }
    }
    rt_exit_critical();
    rt_kprintf(buff_start);

return 0;
}
MSH_CMD_EXPORT(list_fd, list file descriptor);
```