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/tcpclient.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/tcpclient.c')
| -rw-r--r-- | examples/network/tcpclient.c | 128 |
1 files changed, 71 insertions, 57 deletions
diff --git a/examples/network/tcpclient.c b/examples/network/tcpclient.c index 559a108d46..73f028655a 100644 --- a/examples/network/tcpclient.c +++ b/examples/network/tcpclient.c @@ -1,81 +1,95 @@ #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 */
-static const char send_data[] = "This is TCP Client from RT-Thread.";
+static const char send_data[] = "This is TCP Client from RT-Thread."; /* 发送用到的数据 */
void tcpclient(const char* url, int port)
{
- char *recv_data;
- struct hostent *host;
- int sock, bytes_received;
- struct sockaddr_in server_addr;
+ char *recv_data;
+ struct hostent *host;
+ int sock, bytes_received;
+ struct sockaddr_in server_addr;
- host = 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 = gethostbyname(url);
- recv_data = rt_malloc(1024);
- if (recv_data == RT_NULL)
- {
- rt_kprintf("No memory\n");
- return;
- }
+ /* 分配用于存放接收数据的缓冲 */
+ recv_data = rt_malloc(1024);
+ if (recv_data == RT_NULL)
+ {
+ rt_kprintf("No memory\n");
+ return;
+ }
- if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)
- {
- rt_kprintf("Socket error\n");
+ /* 创建一个socket，类型是SOCKET_STREAM，TCP类型 */
+ if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)
+ {
+ /* 创建socket失败 */
+ rt_kprintf("Socket error\n");
- /* release recv buffer */
- rt_free(recv_data);
- return;
- }
+ /* 释放接收缓冲 */
+ rt_free(recv_data);
+ 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));
- if (connect(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1)
- {
- rt_kprintf("Connect error\n");
+ /* 连接到服务端 */
+ if (connect(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1)
+ {
+ /* 连接失败 */
+ rt_kprintf("Connect error\n");
- /* release recv buffer */
- rt_free(recv_data);
- return;
- }
+ /*释放接收缓冲 */
+ rt_free(recv_data);
+ return;
+ }
- while(1)
- {
- bytes_received = recv(sock, recv_data, 1024, 0);
- if (bytes_received < 0)
- {
- lwip_close(sock);
+ while(1)
+ {
+ /* 从sock连接中接收最大1024字节数据 */
+ bytes_received = recv(sock, recv_data, 1024, 0);
+ if (bytes_received < 0)
+ {
+ /* 接收失败，关闭这个连接 */
+ lwip_close(sock);
- /* release recv buffer */
- rt_free(recv_data);
- break;
- }
+ /* 释放接收缓冲 */
+ rt_free(recv_data);
+ break;
+ }
- recv_data[bytes_received] = '\0';
+ /* 有接收到数据，把末端清零 */
+ recv_data[bytes_received] = '\0';
- if (strcmp(recv_data , "q") == 0 || strcmp(recv_data , "Q") == 0)
- {
- lwip_close(sock);
+ if (strcmp(recv_data , "q") == 0 || strcmp(recv_data , "Q") == 0)
+ {
+ /* 如果是首字母是q或Q，关闭这个连接 */
+ lwip_close(sock);
- /* release recv buffer */
- rt_free(recv_data);
- break;
- }
- else
- {
- rt_kprintf("\nRecieved data = %s " , recv_data);
- }
+ /* 释放接收缓冲 */
+ rt_free(recv_data);
+ break;
+ }
+ else
+ {
+ /* 在控制终端显示收到的数据 */
+ rt_kprintf("\nRecieved data = %s " , recv_data);
+ }
- send(sock,send_data,strlen(send_data), 0);
- }
+ /* 发送数据到sock连接 */
+ send(sock,send_data,strlen(send_data), 0);
+ }
- return;
+ return;
}
#ifdef RT_USING_FINSH
#include <finsh.h>
+/* 输出tcpclient函数到finsh shell中 */
FINSH_FUNCTION_EXPORT(tcpclient, startup tcp client);
#endif
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