| lwIP
    2.0.3
    Lightweight IP stack | 
#include <api_msg.h>
| Data Fields | |
| const char * | name | 
| ip_addr_t * | addr | 
| u8_t | dns_addrtype | 
| sys_sem_t * | sem | 
| err_t * | err | 
As lwip_netconn_do_gethostbyname requires more arguments but doesn't require a netconn, it has its own struct (to avoid struct api_msg getting bigger than necessary). lwip_netconn_do_gethostbyname must be called using tcpip_callback instead of tcpip_apimsg (see netconn_gethostbyname).
| ip_addr_t* dns_api_msg::addr | 
The resolved address is stored here
| u8_t dns_api_msg::dns_addrtype | 
Type of resolve call
| err_t* dns_api_msg::err | 
Errors are given back here
| const char* dns_api_msg::name | 
Hostname to query or dotted IP address string
| sys_sem_t* dns_api_msg::sem | 
This semaphore is posted when the name is resolved, the application thread should wait on it.