diff options
| author | bernard.xiong <[email protected]> | 2010-03-24 15:26:48 +0000 |
|---|---|---|
| committer | bernard.xiong <[email protected]> | 2010-03-24 15:26:48 +0000 |
| commit | cd039a8b49add8238c4e721bdebcaabcccdd99b9 (patch) | |
| tree | 28c975ff403226d4cac0e42f7005226856328c9c /examples/network/udpclient.c | |
| parent | 7606f6d952aa509cbd88ea735d8f3c0d73cd48d0 (diff) | |
add more Chinese comments.
git-svn-id: https://rt-thread.googlecode.com/svn/trunk@536 bbd45198-f89e-11dd-88c7-29a3b14d5316
Diffstat (limited to 'examples/network/udpclient.c')
| -rw-r--r-- | examples/network/udpclient.c | 58 |
1 files changed, 33 insertions, 25 deletions
diff --git a/examples/network/udpclient.c b/examples/network/udpclient.c index 5634627cdb..041adb32c5 100644 --- a/examples/network/udpclient.c +++ b/examples/network/udpclient.c @@ -1,42 +1,50 @@ #include <rtthread.h>
-#include <lwip/netdb.h>
-#include <lwip/sockets.h>
+#include <lwip/netdb.h> /* 为了解析主机名，需要包含netdb.h头文件 */
+#include <lwip/sockets.h> /* 使用BSD socket，需要包含sockets.h头文件 */
-const char send_data[] = "This is UDP Client from RT-Thread.\n";
+const char send_data[] = "This is UDP Client from RT-Thread.\n"; /* 发送用到的数据 */
void udpclient(const char* url, int port, int count)
{
- int sock;
- struct hostent *host;
- struct sockaddr_in server_addr;
+ int sock;
+ struct hostent *host;
+ struct sockaddr_in server_addr;
- host= (struct hostent *) gethostbyname(url);
+ /* 通过函数入口参数url获得host地址（如果是域名，会做域名解析） */
+ host= (struct hostent *) gethostbyname(url);
- if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
- {
- rt_kprintf("Socket error\n");
- return;
- }
+ /* 创建一个socket，类型是SOCK_DGRAM，UDP类型 */
+ 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));
+ /* 初始化预连接的服务端地址 */
+ 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));
+ /* 总计发送count次数据 */
+ while (count)
+ {
+ /* 发送数据到服务远端 */
+ sendto(sock, send_data, strlen(send_data), 0,
+ (struct sockaddr *)&server_addr, sizeof(struct sockaddr));
- rt_thread_delay(50);
+ /* 线程休眠一段时间 */
+ rt_thread_delay(50);
- count --;
- }
+ /* 计数值减一 */
+ count --;
+ }
- /* close socket */
- lwip_close(sock);
+ /* 关闭这个socket */
+ lwip_close(sock);
}
#ifdef RT_USING_FINSH
#include <finsh.h>
+/* 输出udpclient函数到finsh shell中 */
FINSH_FUNCTION_EXPORT(udpclient, startup udp client);
#endif
|