rt-thread/examples/network/udpclient.c

#include <rtthread.h>
#include <lwip/netdb.h>
#include <lwip/sockets.h>

const char send_data[] = "This is UDP Client from RT-Thread.\n";
void udpclient(const char* url, int port, int count)
{
	int sock;
	struct hostent *host;
	struct sockaddr_in server_addr;

	host= (struct hostent *) gethostbyname(url);

	if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
	{
		rt_kprintf("Socket error\n");
		return;
	}

	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(port);
	server_addr.sin_addr = *((struct in_addr *)host->h_addr);
	rt_memset(&(server_addr.sin_zero), 0, sizeof(server_addr.sin_zero));

	while (count)
	{
		sendto(sock, send_data, strlen(send_data), 0,
		   (struct sockaddr *)&server_addr, sizeof(struct sockaddr));

        rt_thread_delay(50);

        count --;
	}

    /* close socket */
	lwip_close(sock);
}

#ifdef RT_USING_FINSH
#include <finsh.h>
FINSH_FUNCTION_EXPORT(udpclient, startup udp client);
#endif