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c++ - 这是合法的 C++ 代码吗？

转载 作者：太空狗 更新时间：2023-10-29 23:34:21 31 4
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代码来自here

鉴于在 C++ 中您可以使用 C 库，您认为以下代码是合法的 C++ 代码吗？如果不是，需要应用哪些更改？

此代码使用 g++ 编译并按预期运行。

更新:谢谢你的所有回答。我仍然有点困惑，因为没有就此代码是否符合 C++ 标准达成一致。会再问一个问题打消我的疑虑

更新 2:对于关闭此问题的版主:刚刚注意到这个问题已经结束，我认为这很荒谬。这是一个实际的技术问题，我收到了实际的技术答案。如果您没有完整阅读整个主题，这里是我们达成一致的结论的直观表示:

alt text

显然 C++ 不是 C 的超集。

结束涉及编码标准的问题是错误的。

客户:

    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <errno.h>
    #include <string.h>
    #include <netdb.h>
    #include <sys/types.h>
    #include <netinet/in.h>
    #include <sys/socket.h>

    #include <arpa/inet.h>
    #define PORT "3490" // the port client will be connecting to 
    #define MAXDATASIZE 100 // max number of bytes we can get at once 

    // get sockaddr, IPv4 or IPv6:
    void *get_in_addr(struct sockaddr *sa){
        if (sa->sa_family == AF_INET) {
            return &(((struct sockaddr_in*)sa)->sin_addr);
        }

        return &(((struct sockaddr_in6*)sa)->sin6_addr);
    }

    int main(int argc, char *argv[]){
        int sockfd, numbytes;  
        char buf[MAXDATASIZE];
        struct addrinfo hints, *servinfo, *p;
        int rv;
        char s[INET6_ADDRSTRLEN];

        if (argc != 2) {
            fprintf(stderr,"usage: client hostname\n");
            exit(1);
        }

        memset(&hints, 0, sizeof hints);
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;

        if ((rv = getaddrinfo(argv[1], PORT, &hints, &servinfo)) != 0) {
            fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
            return 1;
        }

        // loop through all the results and connect to the first we can
        for(p = servinfo; p != NULL; p = p->ai_next) {
            if ((sockfd = socket(p->ai_family, p->ai_socktype,
                    p->ai_protocol)) == -1) {
                perror("client: socket");
                continue;
            }

            if (connect(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
                close(sockfd);
                perror("client: connect");
                continue;
            }

            break;
        }

        if (p == NULL) {
            fprintf(stderr, "client: failed to connect\n");
            return 2;
        }

        inet_ntop(p->ai_family, get_in_addr((struct sockaddr *)p->ai_addr),
                s, sizeof s);
        printf("client: connecting to %s\n", s);

        freeaddrinfo(servinfo); // all done with this structure

        if ((numbytes = recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1) {
            perror("recv");
            exit(1);
        }

        buf[numbytes] = '\0';
        printf("client: received '%s'\n",buf);
        close(sockfd);

        return 0;
    }

服务器:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <signal.h>

#define PORT "3490"  // the port users will be connecting to
#define BACKLOG 10     // how many pending connections queue will hold

void sigchld_handler(int s){
    while(waitpid(-1, NULL, WNOHANG) > 0);
}

// get sockaddr, IPv4 or IPv6:
void *get_in_addr(struct sockaddr *sa){
    if (sa->sa_family == AF_INET) {
        return &(((struct sockaddr_in*)sa)->sin_addr);
    }

    return &(((struct sockaddr_in6*)sa)->sin6_addr);
}

int main(void){
    int sockfd, new_fd;  // listen on sock_fd, new connection on new_fd
    struct addrinfo hints, *servinfo, *p;
    struct sockaddr_storage their_addr; // connector's address information
    socklen_t sin_size;
    struct sigaction sa;
    int yes=1;
    char s[INET6_ADDRSTRLEN];
    int rv;

    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags = AI_PASSIVE; // use my IP

    if ((rv = getaddrinfo(NULL, PORT, &hints, &servinfo)) != 0) {
        fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
        return 1;
    }

    // loop through all the results and bind to the first we can
    for(p = servinfo; p != NULL; p = p->ai_next) {
        if ((sockfd = socket(p->ai_family, p->ai_socktype,
                p->ai_protocol)) == -1) {
            perror("server: socket");
            continue;
        }

        if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes,
                sizeof(int)) == -1) {
            perror("setsockopt");
            exit(1);
        }

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

        break;
    }

    if (p == NULL)  {
        fprintf(stderr, "server: failed to bind\n");
        return 2;
    }

    freeaddrinfo(servinfo); // all done with this structure

    if (listen(sockfd, BACKLOG) == -1) {
        perror("listen");
        exit(1);
    }

    sa.sa_handler = sigchld_handler; // reap all dead processes
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_RESTART;
    if (sigaction(SIGCHLD, &sa, NULL) == -1) {
        perror("sigaction");
        exit(1);
    }

    printf("server: waiting for connections...\n");

    while(1) {  // main accept() loop
        sin_size = sizeof their_addr;
        new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size);
        if (new_fd == -1) {
            perror("accept");
            continue;
        }

        inet_ntop(their_addr.ss_family,
            get_in_addr((struct sockaddr *)&their_addr),
            s, sizeof s);
        printf("server: got connection from %s\n", s);

        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);
        }
        close(new_fd);  // parent doesn't need this
    }

    return 0;
}

31 4 0
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