C Windows下判断是否能ping通

1. system在能ping通或无法访问目标主机的情况返回0，ping包丢失(请求超时)则返回1：

#include "stdafx.h"
#include <string>
#include <iostream>
using namespace std;
int main(int argc, char * argv[]) {
    

    string a = "192.168.70.2";
    char buffer[128];
    sprintf_s(buffer,"ping %s -n 1",a.c_str());
    int res=system(buffer);
    cout << "返回:" << res << endl;

    res=system("ping 163.com -n 1");

    cout << "返回:" << res << endl;
    system("pause");
    return 0;
}

2. 用微软接口函数IcmpSendEcho2发送icmp包

int ping(string IP){

    // Declare and initialize variables

    HANDLE hIcmpFile;
    unsigned long ipaddr = INADDR_NONE;
    DWORD dwRetVal = 0;
    DWORD dwError = 0;
    char SendData[] = "Data Buffer";
    LPVOID ReplyBuffer = NULL;
    DWORD ReplySize = 0;

    // Validate the parameters



    char * ip = (char*)IP.c_str();
    //ipaddr = inet_addr(ip);
    inet_pton(AF_INET, ip, &ipaddr);

    hIcmpFile = IcmpCreateFile();
    if (hIcmpFile == INVALID_HANDLE_VALUE) {
        printf("\tUnable to open handle.\n");
        printf("IcmpCreatefile returned error: %ld\n", GetLastError());
        return 1;
    }
    // Allocate space for at a single reply
    ReplySize = sizeof(ICMP_ECHO_REPLY) + sizeof(SendData) + 8;
    ReplyBuffer = (VOID *)malloc(ReplySize);
    if (ReplyBuffer == NULL) {
        printf("\tUnable to allocate memory for reply buffer\n");
        return 1;
    }

    dwRetVal = IcmpSendEcho2(hIcmpFile, NULL, NULL, NULL,
        ipaddr, SendData, sizeof(SendData), NULL,
        ReplyBuffer, ReplySize, 1000);
    if (dwRetVal != 0) {
        PICMP_ECHO_REPLY pEchoReply = (PICMP_ECHO_REPLY)ReplyBuffer;
        struct in_addr ReplyAddr;
        ReplyAddr.S_un.S_addr = pEchoReply->Address;
        printf("\tSent icmp message to %s\n", ip);
        if (dwRetVal > 1) {
            printf("\tReceived %ld icmp message responses\n", dwRetVal);
            printf("\tInformation from the first response:\n");
        }
        else {
            printf("\tReceived %ld icmp message response\n", dwRetVal);
            printf("\tInformation from this response:\n");
        }

        //printf("\t  Received from %s\n", inet_ntoa(ReplyAddr));
        printf("\t  Status = %ld  ", pEchoReply->Status);
        switch (pEchoReply->Status) {
        case IP_DEST_HOST_UNREACHABLE:
            printf("(Destination host was unreachable)\n");
            break;
        case IP_DEST_NET_UNREACHABLE:
            printf("(Destination Network was unreachable)\n");
            break;
        case IP_REQ_TIMED_OUT:
            printf("(Request timed out)\n");
            break;
        default:
            printf("\n");
            break;
        }

        printf("\t  Roundtrip time = %ld milliseconds\n",
            pEchoReply->RoundTripTime);
    }
    else {
        printf("Call to IcmpSendEcho2 failed.\n");
        dwError = GetLastError();
        switch (dwError) {
        case IP_BUF_TOO_SMALL:
            printf("\tReplyBufferSize to small\n");
            break;
        case IP_REQ_TIMED_OUT:
            printf("\tRequest timed out\n");
            break;
        default:
            printf("\tExtended error returned: %ld\n", dwError);
            break;
        }
        return 1;
    }
    return 0;
}