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Question

我一直在关注Beej Networking指南,在服务器部分,有一部分代码叫做函数fork().

if (!fork()) { // this is the child process
            close(sockfd); // child doesn't need the listener
            if (send(new_fd, "Hello, world!", 13, 0) == -1)
                perror("send");
            close(new_fd);
            exit(0);

我在Windows机器上,不能让那部分工作.我能做些什么来解决这个问题？我的代码如下.

/* Server */
#define _WIN32_WINNT 0x501
#include <iostream>
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#include  <sys/types.h>


using namespace std;

const int winsockVersion = 2;
#define BACKLOG 10
#define PORT "3000"


int main(void){

    WSADATA wsadata;
    if (WSAStartup(MAKEWORD(winsockVersion,0),&wsadata) == 0){
        cout<<"-WSAStartup initialized..." << endl;

        int status;
        int sockfd, new_fd;
        const char yes = '1';
        struct addrinfo hints, *res,*loop_find;
        struct sockaddr_storage their_addr;
        socklen_t addr_size;



        memset(&hints,0,sizeof hints);
        hints.ai_family = AF_INET;
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_flags = AI_PASSIVE;

        if ( (status = getaddrinfo(NULL,PORT,&hints,&res)) == 0 ){
            cout<<"-Call to get addrinfo successful!." << endl;
        }

        for (loop_find = res; loop_find!=NULL; loop_find = loop_find->ai_next){
            if ( (sockfd = socket(loop_find->ai_family,loop_find->ai_socktype,loop_find->ai_protocol) ) == -1 ){
                cout<<"-Could not create socket." << endl;
                continue;
            }else{
                cout<<"-Socket Created." << endl;
            }

            //clearing in use ports.
            if (setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&yes,sizeof(int)) == -1) {
                cout<<"-Couldnt clear blocked port." << endl;
                perror("setsockopt");
                exit(1);
            }

            if( bind(sockfd,loop_find->ai_addr,loop_find->ai_addrlen) == -1 ){
                closesocket(sockfd);
                perror("server: bind");
                continue;
            }

            break;
        }

        if (listen(sockfd,BACKLOG) != -1){
            cout<<"-Listening for incoming connections.";
        }

        //accept loop.
        while(true){

            socklen_t addr_size = sizeof their_addr;
            new_fd = accept(sockfd,(sockaddr*)&their_addr,&addr_size);

            if ( new_fd == -1 ){
                perror("accept");
                continue;
            }

            struct sockaddr new_addr;
            int len = sizeof new_addr;
            getpeername(new_fd,&new_addr,&len);
            cout<<"-Connected to " << new_addr.sa_data << endl;

            if(!fork()){ //this is a child process
                closesocket(sockfd);
                if (send(new_fd,"hello world!!",13,0) == -1){
                    perror("send");
                    closesocket(new_fd);
                    exit(0);
                }
            }
            closesocket(new_fd);

        }
    }


    //clear stuff
    if( WSACleanup() != 0){
        cout<<"-WSACleanup unsuccessful" << endl;
    }else{
        cout<<"-WSACleanup successful" << endl;
    }


    return 0;

}

Answer 1

与现有答案(来自OJ和Vincent Robert)相反,fork()确实存在于高端版本的Windows上.它是以前称为Microsoft Windows Services for UNIX(SFU)的基于UNIX的应用程序子系统(SUA)的一部分,之前称为Interix.

引用http://en.wikipedia.org/wiki/Interix,SUA可用

• Windows Server 2003 R2(所有版本) - 5.2版
• Windows Vista(Ultimate和Enterprise版本) - 6.0版
• Windows Server 2008(所有版本) - 6.0版
• Windows Server 2008 R2和Microsoft Windows 7 - 版本6.1

使用fork()所需要做的就是安装免费的SUA SDK.根据您的目标系统,您需要以下之一:

• 基于UNIX的应用程序子系统的实用程序和软件开发工具包(SDK)
• Microsoft Windows Vista RTM/Windows Vista SP1和Windows Server 2008 RTM中基于UNIX的应用程序子系统的实用程序和SDK
• Microsoft Windows 7和Windows Server 2008 R2中基于UNIX的应用程序子系统的实用程序和SDK

您还可以看看Doix是否实现了fork()？

Answer 2

fork()显然在Windows上不存在.相反,您需要创建一个新线程或一个全新的过程.

Answer 3

fork在Windows上不存在.您必须使用名为Window的特定API CreateProcess.

相反fork,CreateProcess需要通往EXE的路径.您可以通过GetModuleFileName使用NULL参数调用来检索当前EXE的路径.