用ulog_file输出日志文件生成的第一份ulog.log.x文件内容有问题

发布于 2021-11-11 15:38:53 浏览：1861 订阅该版

![image.png](https://oss-club.rt-thread.org/uploads/20211111/89e6533a35a169fec4df6fc7e2481c50.png)

```
int main(void)
{
//    LOG_D("Hello RT-Thread!");
    set_date(2018, 12, 11);
    set_time(11, 15, 50);
    fal_init();

struct rt_device *flash_dev = fal_mtd_nor_device_create(FS_PARTITION_NAME);

if (flash_dev == NULL)
    {
        LOG_E("Can't create a mtd device on '%s' partition.\n", FS_PARTITION_NAME);
    }
    else
    {
        LOG_I("Create a mtd device on the %s partition of flash successful.\n", FS_PARTITION_NAME);
    }

if(rt_device_find(FS_PARTITION_NAME) != RT_NULL)
    {
        /* 挂载 littlefs */
        if (dfs_mount(FS_PARTITION_NAME, "/", "lfs", 0, 0) == 0)
        {
            ulog_file_backend_init();
            LOG_I("Filesystem initialized!");
            LOG_D("Hello RT-Thread!");
            LOG_I("Filesystem initialized!");
            LOG_D("Hello RT-Thread!");
        }
        else
        {
            /* 格式化文件系统 */
            dfs_mkfs("lfs", FS_PARTITION_NAME);
            /* 挂载 littlefs */
            if (dfs_mount(FS_PARTITION_NAME, "/", "lfs", 0, 0) == 0)
            {
                ulog_file_backend_init();
                LOG_I("Filesystem initialized!");
            }
            else
            {
                LOG_E("Failed to initialize filesystem!");
            }
        }
    }
    else
    {
        LOG_E("find filesystem portion failed\r\n");
    }

rt_uint8_t i=0;
    while(i++<25)
    {
        LOG_D("Hello RT-Thread!");
        LOG_I("Filesystem initialized!");
    }

return RT_EOK;
}

```

只有上电后输出的第一份文件是这样，之后的文件内容都是正常的
![image.png](https://oss-club.rt-thread.org/uploads/20211111/9f12082bc880e1ea4ea2ee6ce9b42fae.png)

控制台打印的信息都是对的

4 个回答

Joy_Lu 2021-11-11

EL・PSY・KONGROO

一通乱找也没找到原因，然后就只是在ulog_file_backend_output
```
static void ulog_file_backend_output(struct ulog_backend *backend, rt_uint32_t level,
            const char *tag, rt_bool_t is_raw, const char *log, size_t len)
{
    size_t file_size = 0;

/* check log file directory  */
    if (access(ULOG_FILE_ROOT_PATH, 0) < 0)
    {
        mkdir(ULOG_FILE_ROOT_PATH, 0);
    }

if (g_file_fd < 0)
    {
        rt_snprintf(g_file_path, ULOG_FILE_PATH_LEN, "%s/%s", ULOG_FILE_ROOT_PATH, ULOG_FILE_NAME_BASE);
        g_file_fd = open(g_file_path, O_CREAT | O_RDWR | O_APPEND);
//        g_file_fd = open(g_file_path, O_CREAT | O_RDWR);
        if (g_file_fd < 0)
        {
            rt_kprintf("ulog file(%s) open failed.", g_file_path);
            return;
        }
    }

file_size = lseek(g_file_fd, 0, SEEK_END);
    if (file_size > ULOG_FILE_MAX_SIZE)
    {
        if (!ulog_file_rotate())
        {
            return;
        }
    }

write(g_file_fd, log, len);
    /* flush file cache */
    fsync(g_file_fd);
}

```
这个函数的open里加上了O_APPEND，然后就好了，不知道可不可以这样改?