10 sqlite软件包内存泄漏

void app_sqlite3_thread(void *argument)
{
    sqlite3_initialize();
    sqlite3 *db;
    char *zErrMsg = 0;
    int res;
    int start = 0;
    int index = 0;
    char cmd[128] = {0};
    time_t now;
    rt_thread_mdelay(2000);
    res = sqlite3_open("/mnt/sd1/test.db", &db);
    if (res != 0)
    {
        LOG_E("open db fail");
        rt_thread_mdelay(1000);
        return;
    }
    res = sqlite3_exec(db, "create table if not exists mydb(time vchar(30),fs1_1 float,fs1_2 float,fs2_1 float,fs2_2 float,fs3_1 float,fs3_2 float,temp1 char,temp2 char,temp3 char,current1 char,current2 char,current3 char,freq1 char,freq2 char,freq3 char)", 0, 0, &zErrMsg);
    if (res != 0)
    {
        LOG_E("create table fail");
        sqlite3_free(zErrMsg);
        rt_thread_mdelay(1000);
        return;
    }
    res = sqlite3_exec(db, "PRAGMA synchronous=FULL", 0, 0, &zErrMsg);
    if (res != 0)
    {
        printf("set pragma fail\r\n");
        sqlite3_free(zErrMsg);
    }
    while (1)
    {
        // printf("start: %d\r\n", rt_tick_get());
        start = rt_tick_get();
        rt_memset(cmd, 0, sizeof(cmd));
        now = time(RT_NULL);
        rt_sprintf(cmd, "insert into mydb values('%s',1.2,2.6,3.1,4.7,0.9,4.2,10,25,28,12,36,28,30,19,24)", ctime(&now));
        res = sqlite3_exec(db, cmd, 0, 0, &zErrMsg);
        if (res != 0)
        {
            LOG_E("insert data fail");
            sqlite3_free(zErrMsg);
        }
        if (rt_tick_get() - start > 100)
        {
            // LOG_W("write time too long: %d",rt_tick_get() - start);
        }
        rt_thread_mdelay(20);
    }
    sqlite3_close(db);
}
int app_sqlite(void)
{
    rt_thread_t tid = 0;
    tid = rt_thread_create("app_sqlite", app_sqlite3_thread, RT_NULL, 500 * 1024, 10, 300);
    if (tid != RT_NULL)
    {
        rt_thread_startup(tid);
    }
    else
        rt_kprintf("create sqlite app fail\r\n");
}
INIT_APP_EXPORT(app_sqlite);