C套接字（Linux）无法连接

Question

recently I've been trying to do a lot with C sockets as it is a language I need for future use. However I've encountered this problem I can't manage to solve. I made both client and server - unfortunately the two binaries refuse to connect in between each other. What I mean is that I do not get any error whatsoever when I run the server binary and client binary in a same machine, but no connection either. Any ideas? Here is the code!

(Ubuntu, both C codes compiled with gcc, server and client code ran within the same machine in 2 different terminals.)

Server.c:

    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h> 
    #include <string.h>
    #include <sys/socket.h>
    #include <arpa/inet.h> //inet_aton(), inet_ntoa() etc
    #include <sys/types.h>
    #include <netinet/in.h>

    #define PORT 8000
    #define ERROR perror("Something went wrong! => ");
    #define BUFFERSIZE 256
    int main()
    {
        int sockfd, client_socketfd; 
        int bytes_sent; 
        socklen_t sin_size;
        struct sockaddr_in server_addr;
        struct sockaddr_in connectedClient_addr;
        char message[BUFFERSIZE] = "Welcome to the server!";

        if((sockfd = socket(PF_INET, SOCK_STREAM ,0)) == -1) {
            ERROR;
            exit(-1);
        }

        server_addr.sin_family = AF_INET;
        server_addr.sin_port   = htons(PORT);
        server_addr.sin_addr.s_addr = INADDR_ANY; //Subject to change


        if((bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr))) == -1) {
            ERROR;
            exit(-2);
        }


        if((listen(sockfd, 5)) == -1) {
            ERROR;
            exit(-3);
        }   

        int addrlen = sizeof(connectedClient_addr);
        if((client_socketfd = accept(sockfd, (struct sockaddr *)&connectedClient_addr, (socklen_t*)&addrlen)) == -1){
            ERROR;
            exit(-4);
        }   

        printf("Got a connection from: %s at port: %d" , inet_ntoa(connectedClient_addr.sin_addr), PORT);

        if((send(sockfd, &message, BUFFERSIZE, 0)) == -1) {
             ERROR;
             exit(-5);
        }

         close(sockfd);
         close(client_socketfd);

        return 0;
    }

--

Client.c:

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


#define PORT 8000
#define ERROR perror("Something went wrong! =>");
#define BUFFERSIZE 256
int main()
{
    int sockfd;
    struct sockaddr_in client_addr;
    char message[BUFFERSIZE] = "Successfully connected!";
    int bytes_received, bytes_sent;
    char buffer[BUFFERSIZE];


    if((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
        ERROR;
        exit(-1);
    }


    client_addr.sin_family = AF_INET;
    client_addr.sin_port   = htons(PORT);
    client_addr.sin_addr.s_addr = INADDR_ANY;


    if((connect(sockfd, (struct sockaddr*)&client_addr, sizeof(client_addr))) == -1) {
        ERROR;
        exit(-2);
    }

    if((bytes_received = recv(sockfd, &buffer, BUFFERSIZE, 0)) == -1) {
        ERROR;
        exit(-3);
    }

    printf("Received %d bytes:\n" , bytes_received);
    printf("%s", buffer);

    close(sockfd);

    return 0;
}

Answer 1

ANSWER: The issue was that I provided server socket inside send() function in server.c instead of the client socket. Therefore the code was working without any errors but the behavior was incorrect. Credit goes to RemyLebeau in the comments who pointed this out and saved me countless hours of more struggling.