C++获取本机IP地址(Win+linux)

获取本机IP地址(Win+linux)

#include <iostream>
#include <optional>
#include <string>

#ifdef _WIN32
#include <winsock2.h>
#include <iphlpapi.h>
#include <stdio.h>
#include <stdlib.h>
#pragma comment(lib, "IPHLPAPI.lib")
#else
#include <sys/types.h>
#include <ifaddrs.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>
#endif

using namespace std;

#define MALLOC(x) HeapAlloc(GetProcessHeap(), 0, (x))
#define FREE(x) HeapFree(GetProcessHeap(), 0, (x))

std::optional<std::string> GetIpAddress()
{
#ifdef _WIN32
	PIP_ADAPTER_INFO pAdapterInfo;
	PIP_ADAPTER_INFO pAdapter = NULL;
	DWORD dwRetVal = 0;

	ULONG ulOutBufLen = sizeof(IP_ADAPTER_INFO);
	pAdapterInfo = (IP_ADAPTER_INFO *)MALLOC(sizeof(IP_ADAPTER_INFO));
	if (pAdapterInfo == NULL) {
		return std::nullopt;
	}
	
	if (GetAdaptersInfo(pAdapterInfo, &ulOutBufLen) == ERROR_BUFFER_OVERFLOW) {
		FREE(pAdapterInfo);
		pAdapterInfo = (IP_ADAPTER_INFO *)MALLOC(ulOutBufLen);
		if (pAdapterInfo == NULL) {
			return std::nullopt;
		}
	}
	
	std::string ip_address;
	if ((dwRetVal = GetAdaptersInfo(pAdapterInfo, &ulOutBufLen)) == NO_ERROR) {
		pAdapter = pAdapterInfo;
		if (pAdapter) {
			ip_address = pAdapter->IpAddressList.IpAddress.String;
		}
	}
	
	if (pAdapterInfo) {
		FREE(pAdapterInfo);
	}
	
	if (!ip_address.empty()) {
		return ip_address;
	}
	return std::nullopt;

#else
	struct ifaddrs * ifAddrStruct = NULL;
	struct ifaddrs * ifa = NULL;
	void * tmpAddrPtr = NULL;

	getifaddrs(&ifAddrStruct);
	std::string ip_address;
	for (ifa = ifAddrStruct; ifa != NULL; ifa = ifa->ifa_next) {
		if (!ifa->ifa_addr) {
			continue;
		}
		if (ifa->ifa_addr->sa_family == AF_INET) { // check it is IP4
		  // is a valid IP4 Address
			tmpAddrPtr = &((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
			char addressBuffer[INET_ADDRSTRLEN];
			inet_ntop(AF_INET, tmpAddrPtr, addressBuffer, INET_ADDRSTRLEN);
	
			if (strcmp(ifa->ifa_name, "lo")) {
				continue;
			}
			else {
				ip_address = addressBuffer;
				if (!ip_address.empty()) {
					break;
				}
			}
		}
	}
	if (ifAddrStruct != NULL) freeifaddrs(ifAddrStruct);
	if (!ip_address.empty()) {
		return ip_address;
	}
	else {
		return std::nullopt;
	}

#endif
}

int main()
{
	auto res =  GetIpAddress();
	if (res.has_value())
	{
		auto ip = res.value();
		std::cout << ip << std::endl;
	}
    std::cout << "Hello World!
";
}

参考链接：https://docs.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-getadaptersinfo