控制台应用程序运行时问题

Question

我的控制台应用程序有问题。我正在学习某种关于网络的教程，当我尝试在调试中运行时，我有一个以前从未见过的奇怪的运行时错误。

当我在主函数中的第一个新行上放置一个断点并使用Step Over (F10)遍历代码时，visual将执行包括WSAStartup()在内的前3行代码，然后突然到达acomment部分：

#include <winsock2.h>
#include <WS2tcpip.h>

#include <iostream>

#include "wsh_includes.h"

int main(int argc, const char* argv[])
{
//You have to make a call to WSAStartup() before doing anything else with the sockets library

    //WSADATA wsaData; // if this doesn't work
    WSAData wsaData; // then try this instead
    wsh::errcheck(WSAStartup(MAKEWORD(2, 2), &wsaData), "WSAStartup failed");

    //----------
    //You also have to tell your compiler to link in the Winsock library, usually called
    //wsock32.lib or winsock32.lib, or ws2_32.lib for Winsock 2.0
    //----------
    //you can't use close() to close a socket—you need to use closesocket()
    //----------
    //select() only works with socket descriptors, not file descriptors (like 0 for stdin).
    //There is also a socket class that you can use, CSocket
    //----------

    int status;
    addrinfo hints, *res, *p;
    char ipstr[INET6_ADDRSTRLEN];

    memset(&hints, 0, sizeof(hints)); //make sure it's empty
    hints.ai_family = AF_UNSPEC; // AF_INET or AF_INET6 to force version
    hints.ai_socktype = SOCK_STREAM; //TCP stream sockets

    status = getaddrinfo("www.example.net", NULL, &hints, &res);
    wsh::errcheck(status, "getaddrinfo failed");

    //servinfo now points to a linked list of 1 or more struct addrinfos
    //... do everything until you don't need servinfo anymore ...

    printf("IP addresses for %s:\n\n", argv[1]);

    for (p = res; p != NULL; p = p->ai_next) {
        void* addr;
        char* ipver;

        //get the pointer to the address itself
        //different fields in IPv4 and IPv6:
        if (p->ai_family == AF_INET) {
            sockaddr_in* ipv4 = (sockaddr_in*)p->ai_addr;
            addr = &(ipv4->sin_addr);
            ipver = "IPv4";
        }
        else {
            sockaddr_in6* ipv6 = (sockaddr_in6*)p->ai_addr;
            addr = &(ipv6->sin6_addr);
            ipver = "IPv6";
        }

        //convert the IP to a string and print it:
        inet_ntop(p->ai_family, addr, ipstr, sizeof(ipstr));
        printf("  %s: %s\n", ipver, ipstr);
    }

    std::cin.get();

    freeaddrinfo(res); //free the linked list

//----------
//Finally, you need to call WSACleanup() when you're all through with the sockets library.
    wsh::errcheck(WSACleanup(), "WSACleanup failed");
    return 0;
}

当它到达那里时，它突然移动到注释部分中间的crtexe.c文件。更具体地说，它跳到：

#ifdef WPRFLAG
            __winitenv = envp;
            mainret = wmain(argc, argv, envp);
#else  /* WPRFLAG */
            __initenv = envp;
            mainret = main(argc, argv, envp); //here

然后转到：

#else  /* !defined (_WINMAIN_) && defined (_CRT_APP) */
            if ( !managedapp )
            {
#ifndef _CRT_APP
                exit(mainret); //here

我已经尝试过去掉所有的注释，当我在调试中运行时，代码的行为会有所不同(但并不像预期的那样)。

到底是怎么回事，我该怎么解决呢？

Answer 1

这通常是由不匹配的行尾引起的(有些行以CR/LF结尾，有些以CR或LF结尾)，这导致IDE无法保持代码编辑器和调试器同步。

VS经常识别这种情况，并显示一个对话框，询问是否要使行尾正常化(更多信息请参见What does Visual Studio mean by normalizing line endings? )。

您可以通过使用File->Advanced 菜单项并将LineEndings设置为 (CR )来自己解决这个问题。