esp8266使用函数espconn_gethostbyname()解析失败的问题

ip_addr_t *esp_server_ip;
LOCAL void ICACHE_FLASH_ATTR
user_esp_platform_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
{
struct espconn *pespconn = (struct espconn *)arg;
if (ipaddr != NULL)
os_printf(user_esp_platform_dns_found %d.%d.%d.%d/n,
*((uint8 *)&ipaddr->addr), *((uint8 *)&ipaddr->addr + 1),
*((uint8 *)&ipaddr->addr + 2), *((uint8 *)&ipaddr->addr + 3));
}
void dns_test(void) {
espconn_gethostbyname(pespconn,“iot.espressif.cn”, esp_server_ip,
user_esp_platform_dns_found);
}

如上DSN解析一般会成功但是会有出错的情况，我今天被这个困扰了很久。

ip_addr_t *esp_server_ip;

espconn_gethostbyname(pespconn,“iot.espressif.cn”, esp_server_ip,
user_esp_platform_dns_found);

合理的做法是把如上两句改成：

ip_addr_t esp_server_ip;

espconn_gethostbyname(pespconn,“iot.espressif.cn”, &esp_server_ip,
user_esp_platform_dns_found);