V-REP与C++初步通信测试

打开vrep，在上方操作栏找到help选项打开，选择help topics。此时浏览器打开了vrep的操作手册user manual。

在user manual左侧目录中找到writing code in and around V-REP，子目录选择V-REP API framework，子目录选择Remote API，从Enabling the Remote API - client side开始学习。

To use the remote API functionality in your C/C++ application, just include following C-language files in your project:
extApi.h
extApi.c
extApiPlatform.h (contains platform specific code)
extApiPlatform.c (contains platform specific code)
Above files are located in V-REP's installation directory, under programming/remoteApi.
把vrep安装目录内的programming/remoteApi里面所有头文件和源文件复制到C++工程里。

Make sure you have defined NON_MATLAB_PARSING and MAX_EXT_API_CONNECTIONS=255 (and optionally DO_NOT_USE_SHARED_MEMORY) as a preprocessor definition.
预处理器定义NON_MATLAB_PARSING和MAX_EXT_API_CONNECTIONS=255。如果编译器有报错关于shared memory，那么还要定义DO_NOT_USE_SHARED_MEMORY，然后在工程中写一个空的main测试error，根据编译器的错误提示修改。

To enable the remote API on the client side (i.e. your application), call simxStart. See the bubbleRobClient project in the programming directory for an example. This page lists and describes all supported C/C++ remote API functions. V-REP remote API functions can easily be recognized from their "simx"-prefix.
调用函数simxStart以启动远程API。但目前做不到，点击这个函数可以查看其使用方法。vrep函数的特点就是都带有simx前缀。

simxStart:
Description
Starts a communication thread with the server (i.e. V-REP). A same client may start several communication threads (but only one communication thread for a given IP and port). This should be the very first remote API function called on the client side. Make sure to start an appropriate remote API server service on the server side, that will wait for a connection. See also simxFinish. This is a remote API helper function.
启动与服务器的通信线程（即V-REP）。 同一客户端可以启动多个通信线程（但只有一个通信线程用于给定的IP和端口）。 这应该是客户端调用的第一个远程API函数。 确保在服务器端启动适当的远程API服务器服务，该服务将等待连接。 另见simxFinish。 这是一个远程API辅助函数。
C synopsis
simxInt simxStart(const simxChar* connectionAddress, simxInt connectionPort, simxUChar waitUntilConnected, simxUChar doNotReconnectOnceDisconnected, simxInt timeOutInMs,simxInt commThreadCycleInMs)
调用方式，基本上只需要关注connectionPort，这个是自定义的参数（端口号）。
C parameters
connectionAddress: the ip address where the server is located (i.e. V-REP)
直接使用字符串“127.0.0.1”即可
connectionPort: the port number where to connect. Specify a negative port number in order to use shared memory, instead of socket communication.
端口号在哪里连接。 指定负端口号以使用共享内存，而不是套接字通信。端口号是自定义的。
waitUntilConnected: if different from zero, then the function blocks until connected (or timed out).
若非零，则功能将阻塞直到连接建立或超时。设置为true或1。
doNotReconnectOnceDisconnected: if different from zero, then the communication thread will not attempt a second connection if a connection was lost.
若非零，那么如果连接丢失，通信线程将不会尝试第二次连接。设置为true或1。
timeOutInMs:
if positive: the connection time-out in milliseconds for the first connection attempt. In that case, the time-out for blocking function calls is 5000 milliseconds.
if negative: its positive value is the time-out for blocking function calls. In that case, the connection time-out for the first connection attempt is 5000 milliseconds.
若为正值：第一次连接尝试的连接超时（以毫秒为单位）。 在这种情况下，阻塞函数调用的超时为5000毫秒。
若为负值：它的绝对值是阻塞函数调用的超时时间。 在这种情况下，第一次连接尝试的连接超时为5000毫秒。
设置为-5000到5000内任意值。
commThreadCycleInMs: indicates how often data packets are sent back and forth. Reducing this number improves responsiveness, and a default value of 5 is recommended.
表示数据包来回发送的频率。 减少此数字可提高响应速度，建议默认值为5。
C return value
the client ID, or -1 if the connection to the server was not possible (i.e. a timeout was reached). A call to simxStart should always be followed at the end with a call to simxFinish if simxStart didn't return -1.
客户端ID，如果无法连接到服务器，则返回-1（即达到超时）。 如果simxStart没有返回-1，则应始终在调用simxFinish时调用simxStart。

返回，继续学习Enabling the Remote API - server side。只需关注一个内置函数simRemoteApi.start。调用方式也很简单，直接调用，并且只要一个参数，就是自定义的端口号。使用vrep自带场景就可以测试，这里使用tutorials\BubbleRob里面的bubbleRob.ttt，建议建立一个副本。打开这个场景，在左侧模块目录中双击bubbleRob右侧第一个小图标，在空白行调用这个函数simRemoteApi.start(20172)。（20172是自定义的，建议端口号设为20000以上的值以免与其它进程冲突）

编写测试程序，直接写在主函数所在源文件：

#include<iostream>
#include"extApi.h"
void main()
{

　　using namespace std;

　　int Port = 20172;

　　int clientID = simxStart("127.0.0.1", Port, 1, 1, 1000, 5);

　　if (clientID != -1)
　　{
　　　　cout << "V-rep connected.";
　　　　simxFinish(clientID);
　　}
　　else 
　　{
　　　　cout << "V-rep can't be connected.";
　　}

　　cin.get();
　　return;
}

测试开始时，先在vrep界面运行仿真，然后再运行c++工程。命令窗口显示V-rep connected表示测试成功。