c++ - 为什么我在 strcpy_s 之后得到 Debug assertion failed？

Question

我刚开始学习套接字，我得到了这段代码，我必须让端口查找逻辑工作。但问题是我不断收到此运行时错误，我不知道为什么？

// portlookup.cpp
// Given a service name, this program displays the corresponding port number.

#include <iostream>
#pragma comment(lib, "ws2_32.lib")
#include <winsock2.h>
using namespace std;

int main (int argc, char **argv)
{
    char    service[80];    // This string contains name of desired service
    struct  servent *pse;   // pointer to service information entry
    short   port;           // Port # (in Network Byte Order) of desired service

    if (argc < 2)
    {
        cout << "Please specify a service." << endl;

    }

    strcpy_s(service, sizeof(service), argv[1]);

    WORD wVersion = 0x0202;
    WSADATA wsaData;
    int iResult = WSAStartup(wVersion, &wsaData);  // Returns zero if successful
    if (iResult != 0) {
        cout << "Insufficient resources to startup WINSOCK." << endl;
        return 0;
    }

    port = htons( (u_short) atoi(service)); // 1st try to convert string to integer
    if (port == 0) {                        // if that doesn't work, call service function
        pse = getservbyname(service,NULL);
        if (pse) {
            port = pse->s_port;
        }
        else
        {
            cout << "Invalid service request." << endl;
            return INVALID_SOCKET;
        }
    }

    cout << "Service: " << service << endl;
    cout << "Port:    " << htons(port) << endl;

}

Answer 1

您的问题似乎是您没有传递命令行，您检查了 argc < 2，但是当它 < 2 时您仍然执行 strcpy_s。

在 Visual Studio 中，转到项目属性对话框，从那里转到调试页面并将服务名称添加到命令参数

并修复你的参数检查代码

if (argc < 2)
{
    //cout << "Please specify a service." << endl;
    cerr << "error: no service specified." << endl;
    return EXIT_FAILURE; // return some non-zero value to indicate failure.
}