C聊天程序獲取錯誤分段錯誤（核心已轉儲）

Question

我正在用C語言在客戶端和服務器之間構建一個聊天程序。 客戶端將連接到服務器，並向其發送消息。 然后服務器將響應該消息。

如果有另一個客戶端連接到服務器，則新連接將創建一個新線程。 因此，我使用pthread.h在C語言中構建了多線程聊天程序。請參閱下面的server.c和client.c代碼以獲取更多詳細信息。

服務器

#include <pthread.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT 7778

void error(char *msg){
    perror(msg);
    exit(1);
}

void *clientHandler(void*);

int main(){
    printf("INFO enter the main()\n");
    int sockfd, newsockfd, clilen;
    char buffer[256];
    struct sockaddr_in serv_addr, cli_addr;
    int n, threadID;
    pthread_t interrupt;

    printf("INFO before calling socket()\n");
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
        printf("INFO after calling socket()\n");
    if(sockfd < 0)
        error("ERROR opening socket\n");

    printf("INFO before calling bzero()\n");
    bzero((char*) &serv_addr, sizeof(serv_addr));
    printf("INFO after calling socket()\n");

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = INADDR_ANY;
    serv_addr.sin_port = htons(PORT);
    printf("INFO after assigning Internet info\n");

    if(bind(sockfd, (struct sockaddr*) &serv_addr, sizeof(serv_addr)) < 0)    
    {
        error("ERROR on binding\n");
        return 0;
    }
    printf("INFO before calling listen()\n");

    listen(sockfd, 5);

    printf("INFO before entering While(1)\n");
    while(1)
    {
        int re;
        clilen = sizeof(cli_addr);
        printf("INFO before calling accept()\n");
        newsockfd = accept(sockfd, (struct sockaddr*)&cli_addr, &clilen);

        if(newsockfd < 0){
            error("ERROR on accepting\n");
            return 0;
        }
        printf("INFO before calling pthread_create()\n");
        re = pthread_create(&interrupt, NULL, clientHandler, NULL);
        if(re){
            printf("ERROR return code from the pthread_create() is %d\n", re);
        }       
    }
    printf("INFO before calling pthread_exit(NULL)\n");
    pthread_exit(NULL);
    return 0;
}

void *clientHandler(void *param){
    int n, newsockfd;
    newsockfd = *((int*)param);
    char buffer[256];
    bzero(buffer, 256);

    while(1){
        n = read(newsockfd, buffer, 255);

        if(n < 0){
            error("ERROR reading from socket\n");
            pthread_exit(NULL);
        }

        printf("Server received the message: %s", buffer);

        n = write(newsockfd, "Server got it\n", 18);

        if(n < 0){
            error("ERROR writing to socket\n");
            pthread_exit(NULL);
        }
    }
}

客戶端

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#define PORT 7778
#define HOSTNAME "127.0.0.1"

void error(char*msg){
    perror(msg);
    exit(1);
}

int main(){
    int sockfd, n;
    struct sockaddr_in serv_addr;
    struct hostent* server;
    //char *hostname = "127.0.0.1";

    char buffer[256];

    sockfd = socket(AF_INET, SOCK_STREAM, 0);

    if(sockfd < 0)
        error("ERROR opening socket\n");

    server = gethostbyname(HOSTNAME);
    if(server == NULL){
        fprintf(stderr,"ERROR no such host\n");
        exit(0);
    }

    bzero((char*) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;

    bcopy((char*)server->h_addr, (char*)&serv_addr.sin_addr.s_addr, server->h_length);

    serv_addr.sin_port = htons(PORT);

    if(connect(sockfd, &serv_addr, sizeof(serv_addr)) < 0){
        error("ERROR connecting\n");
        return 0;
    }

    while(1)
    {    
        printf("Please enter the message: ");
        bzero(buffer, 256);
        fgets(buffer, 255, stdin);
        n=write(sockfd, buffer, strlen(buffer));

        if(n < 0){
            error("ERROR reading from socket\n");
            return 0;    
        }

        printf("[Server got it] %s\n", buffer);
    }

    return 0;
}

好的，我使用終端在Linux環境中成功構建了* .c文件。

我使用此命令行來構建server.c

gcc server.c -o server.out -pthread

並用它來構建client.c

gcc client.c -o client.out

然后，我調用server.out運行服務器：

 ./server.out

並運行client.out

./client.out 

但是，在我運行server.out時，出現錯誤：

Segmentation fault (core dumped)

伙計們，您能否與我分享您的經驗。 我的代碼在某處錯誤嗎？

Answer 1

該行傳遞NULL作為處理程序的參數

 re = pthread_create(&interrupt, NULL, clientHandler, NULL);

它應該是：

 re = pthread_create(&interrupt, NULL, clientHandler, &newsockfd);

正如Sourav Ghosh所說。

Answer 2

您需要將newsockt id傳遞給創建的新線程。

所以改變

    re = pthread_create(&interrupt, NULL, clientHandler, (void*)&newsockfd);

我在這里添加了第三個參數

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用（void *）進行類型轉換不會給您一個警告:)