我是C ++的新手,我目前正在从tutorial学习如何使用winsock(2)。
但是我的服务器遇到了问题。我不知道怎么回事。
#include "stdafx.h"
#include <WinSock2.h>
#include <winsock.h>
#pragma comment(lib, "Ws2_32.lib")
using namespace std;
void cmdError(string e = ""){
cout << "Error:\n" << e << endl;
chrono::milliseconds t( 3000 );
this_thread::sleep_for( t );
}
void startServer(int port){
SOCKET acceptSocket;
SOCKET connectedSocket;
SOCKADDR_IN addr;
addr.sin_family=AF_INET;
addr.sin_port=htons(port);
addr.sin_addr.s_addr=ADDR_ANY;
memset(&addr, 0, sizeof(SOCKADDR_IN));
long rc;
acceptSocket = socket(AF_INET, SOCK_STREAM, 0);
if(acceptSocket = INVALID_SOCKET){ throw new exception();}
rc = ::bind(acceptSocket, (SOCKADDR*) &addr, sizeof(SOCKADDR_IN));
if(rc == SOCKET_ERROR){ throw new exception();}
rc = listen(acceptSocket, 10);
if(rc == SOCKET_ERROR){ throw new exception();}
connectedSocket = accept(acceptSocket, NULL, NULL);
if(connectedSocket == INVALID_SOCKET){ throw new exception();}
}
void startClient(string ip, int port){
long rc;
SOCKADDR_IN addr;
SOCKET s = socket(AF_INET, SOCK_STREAM, 0);
if(s == INVALID_SOCKET){ throw new exception();}
memset(&addr, 0, sizeof(SOCKADDR_IN));
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
addr.sin_addr.s_addr = inet_addr(ip.c_str());
rc = connect(s, (SOCKADDR*)&addr, sizeof(SOCKADDR));
if(s == SOCKET_ERROR){ throw new exception();}
}
int _tmain(int argc, _TCHAR* argv[]){
WSADATA wsa;
if(WSAStartup(MAKEWORD(2, 0), &wsa) != 0){
cmdError();
return 1;
}
string n;
int port;
cout << "Please specify the task of this thread. \nEnter 'server' or 'client'." << endl;
getline(cin, n);
system("cls");
cout << "Please specify a port." << endl;
cin.clear();
cin.sync();
cin >> port;
system("cls");
if(n.at(0) == 'c' || n.at(0) == 'C'){
string ip;
cout << "You started a client application." << endl;
cout << "Enter the IP address of the server you want to connect to." << endl;
cin.clear();
cin.sync();
getline(cin, ip);
system("cls");
cmdError();
try{
startClient(ip, port);
}
catch(exception e){
cmdError();
e.~exception();
return 1;
}
return 0;
}
else if(n.at(0) == 's' || n.at(0) == 'S'){
cout << "You started a server application" << endl;
try {
startServer(port);
}
catch(exception e){
e.~exception();
return 1;
}
return 0;
}
cmdError();
return 1;
}
void sendStr(string msg){
}
通过应用程序启动服务器时,在
void startServer(int port)
中出现以下错误弹出窗口。First-chance exception at 0x7667C42D in test.exe: Microsoft C++ exception:
std::exception at memory location 0x001EF5C8.
If there is a handler for this exception, the progrram may be safely continued.
知道为什么会这样吗?
最佳答案
您没有抓住所扔的东西。您正在抛出exception *
,并且试图捕获exception
。
您几乎应该永远不会抛出new
异常,您应该仅引发异常,然后应捕获对所述异常的const引用,例如:
#include <exception>
#include <iostream>
int
x(int y)
{
throw std::exception();
}
int
main(int argc, char **argv)
{
try {
x(2);
} catch (const std::exception &e) {
std::cout << "Oops" << std::endl;
}
return 0;
}
如果使用您的代码,则由于未捕获的
std::exception *
类型异常而使程序终止(请注意,它是指向std::exception
的指针,而不是std::exception
。另外,我不知道您想使用
e.~exception();
完成什么。在该代码中没有位置。如果要删除new
d异常,则应delete
删除。像这样对析构函数的显式调用表明您在理解对象生命周期方面遇到困难。这是C++
语言的基本组成部分。查尔斯·贝利(Charles Bailey)的answer to this question也详细介绍了其原因和意义。