erlang 实现与 c++ 通讯
网络通讯常用的有2种：行通讯和包体通讯，也就是常说的文本通讯和二进制通讯。文章分别在两种方式上实现erlang与c++通讯。
一、erlang 与 c++ 行通讯
行通讯是一种文本通讯，格式如“cmd args\n”，比较简单，erlang接收数据也比较简单，可以设置参数{packet, line}，缺点是表示方式单一，很难表示结构数据。
1、erlang 代码（server.erl）：
[plain]
-module(server).
-export([start/0]).
-define( PORT, 5678).
%% 启动服务并接受客户端的连接
start() ->
{ok, LSock} = gen_tcp:listen(?PORT, [binary, {packet, line},{active, false}]),
io:format("socket listen: ~p on ~p ~n",[LSock, ?PORT]),
accept(LSock).
accept(LSock) ->
{ok, ASock} = gen_tcp:accept(LSock),
spawn(fun() -> server_loop(ASock) end),
accept(LSock).
server_loop(ASock) ->
case gen_tcp:recv(ASock, 0) of
{ok, Data} ->
io:format("recv line data: ~p~n", [Data]),
gen_tcp:send(ASock, Data),
server_loop(ASock);
{error, _} ->
{ok, recv_error}
end.
2、c++ 代码（test.cpp）：
[cpp]
#include <winsock2.h>
#include <iostream>
#pragma comment(lib, "ws2_32.lib")
int main(int argc, char* argv[])
{
WSADATA wsaData;
WSAStartup( MAKEWORD( 2, 2 ), &wsaData );
SOCKET sc = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0, NULL);
SOCKADDR_IN addr;
int len=sizeof(addr);
addr.sin_family=AF_INET;
addr.sin_addr.s_addr = inet_addr("127.0.0.1");
addr.sin_port = htons(5678);
connect(sc, (struct sockaddr *)&addr, len);
char buff[1024];
memset(buff, 0, 1024);
char data[] = "aaaaaa\n";
//发送数据
printf("send data: %s \n", data);
send(sc, data, sizeof(data), 0);
//接收数据
recv(sc, buff, 1024, 0);
printf("recv data: %s \n", buff);
closesocket(sc);
WSACleanup();
getchar();
return 0;
}
二、erlang 与 c++ 包体通讯
包体通讯是二进制通讯，目前主要有结构体，json，asn等等，最简单还可以这样定义：2个字节cmd + 2个字节字符长度 + 字符内容。
下面以结构体包体通讯示例：
1、erlang代码（server.erl）：
[plain]
-module(server).
-export([start/0]).
-define( UINT, 32/unsigned-little-integer).
-define( INT, 32/signed-little-integer).
-define( USHORT, 16/unsigned-little-integer).
-define( SHORT, 16/signed-little-integer).
-define( UBYTE, 8/unsigned-little-integer).
-define( BYTE, 8/signed-little-integer).
-define( PORT, 5678).
%% 启动服务并接受客户端的连接
start() ->
{ok, LSock} = gen_tcp:listen(?PORT, [binary, {packet, 0},{active, false}]),
io:format("socket listen: ~p on ~p ~n",[LSock, ?PORT]),
accept(LSock).
accept(LSock) ->
{ok, ASock} = gen_tcp:accept(LSock),
spawn(fun() -> server_loop(ASock) end),
accept(LSock).
server_loop(ASock) ->
case gen_tcp:recv(ASock, 0) of
{ok, <<Len:?USHORT,Cmd:?USHORT,Contain:4/binary-unit:8,_Rest/binary>> = A} ->
%% _Rest 匹配C++字符串后面的结束符/0
io:format("recv data: ~p ~p ~p~n", [Len, Cmd, Contain]),
gen_tcp:send(ASock, A),
server_loop(ASock);
{ok, Data} ->
io:format("recv unformated data: ~p~n", [Data]),
server_loop(ASock);
{error, _} ->
{ok, recv_error}
end.
2、c++ 代码（test.cpp）：
[cpp]
#include <winsock2.h>
#include <iostream>
#pragma comment(lib, "ws2_32.lib")
struct data
{
unsigned short int len;
unsigned short int cmd;
char content[5] ;
};
int main(int argc, char* argv[])
{
WSADATA wsaData;
WSAStartup( MAKEWORD( 2, 2 ), &wsaData );
SOCKET sc = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0, NULL);
SOCKADDR_IN addr;
int len=sizeof(addr);
addr.sin_family=AF_INET;
addr.sin_addr.s_addr = inet_addr("127.0.0.1");
addr.sin_port = htons(5678);
connect(sc, (struct sockaddr *)&addr, len);
char buff[1024];
memset(buff, 0, 1024);
struct data pdata = {4, 1001, "test"};
//发送数据
printf("send data: %d %d %s \n", pdata.len, pdata.cmd, pdata.content);
send(sc, (char *)&pdata, sizeof(pdata), 0);
//接收数据
recv(sc, buff, 1024, 0);
struct data * pdata_get = (struct data *) buff;
printf("recv data: %d %s \n", pdata_get->cmd, pdata_get->content);
closesocket(sc);
WSACleanup();
getchar();
return 0;
}
补充：软件开发 , C++ ,
