C - Creating endless socket connection between server and client (Linux) -

i have simple socket program created in c (using ubuntu), connection works fine, server compiles , client provides ip , port number.

but when connection established, client can send 1 message , connection closes. when client sends message, server receives , program ends itself.

i tried use while loop, gives me error on binding. there way make infinite, when user enters exit or specific key/command, program ends.

server.c updated while loop

#include<stdio.h>   #include<stdlib.h>   #include<sys/types.h>      #include<sys/socket.h>   #include<netinet/in.h>   #include<string.h>    int main(int argc, char *argv[])   {         int sockfd, newsockfd, portnum, clien, n;       char buffer[256];       struct sockaddr_in serv_addr,cli_addr;   if (argc < 2)   {         fprintf(stderr, "\nno port provided");         exit(1);   }    sockfd = socket(af_inet,sock_stream, 0);   if (sockfd < 0)         printf("\nprovide valid port number\n");    bzero((char *)&serv_addr, sizeof(serv_addr));   portnum = atoi(argv[1]);    serv_addr.sin_family = af_inet;   serv_addr.sin_addr.s_addr = inaddr_any;   serv_addr.sin_port = htons(portnum);    if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0 )         printf("error on binding");    while(1)   {        listen(sockfd,5);   }   clien = sizeof(cli_addr);   newsockfd=accept(sockfd, (struct sockaddr *) &cli_addr, &clien );    if (newsockfd < 0)         printf("=> error on accepting...\n");    bzero(buffer, 256);     n = read(newsockfd, buffer, 256);     if (n < 0)           printf("error reading socket...\n");    printf("%s\n", buffer);   n = write(newsockfd, "message received.", 58);    if (n < 0)         printf("cannot write socket...\n");    return 0; } 

client.c updated while loop

#include<stdio.h>   #include<stdlib.h>   #include<sys/types.h>      #include<sys/socket.h>   #include<netinet/in.h>   #include<netdb.h>   #include<string.h>    int main(int argc, char *argv[])   {         int sockfd,portno,n;       char buffer[256];       struct sockaddr_in serv_addr;       struct hostent *server;        //while(counter != 5)       // /{             if (argc < 3)       {               fprintf(stderr,"usage %s hostname port...\n",argv[0]);             exit(1);       }        portno = atoi(argv[2]);       sockfd = socket(af_inet, sock_stream, 0);       if (sockfd < 0)             printf("\error opening socket...\n");        bzero((char *) &serv_addr, sizeof(serv_addr));       server = gethostbyname(argv[1]);        if (server == null)       {             fprintf(stderr,"no such host...\n");             exit(0);       }        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(portno);        if (connect(sockfd, &serv_addr,sizeof(serv_addr)) <0 )               printf("\error connecting\n");        printf("your message:");       fgets(buffer, 256, stdin);       while(1)       {             n = write(sockfd,buffer,strlen(buffer));       }       if (n < 0)             printf("error writing socket\n");        n = read(sockfd, buffer, 255);        if (n < 0)             printf("error reading socket\n");        printf("%s\n", buffer);                  return 0; } 

thank you.

the problem server terminate whenever receive message. should keep on listening recv() function until client disconnects. here 1 piece of code should trick.

disclaimer: haven't tested it, it's old project modified on fly it's supposed work i'm not 100% sure does, have no time test right feel free ask questions if there wrong, i'll try correct it.

edit: trying re-bing causes error because binding done , port busy cannot "assign" other program port therefore giving error. thing have make sure server listens until client disconnects server.

also, possible of code made c++ @ point, networking part should work fine.

feel free try out , comment if have questions. server.c:

    int socket_desc , client_sock , c , *new_sock;     struct sockaddr_in server , client;      socket_desc = socket(af_inet , sock_stream , 0);     if (socket_desc == -1)     {         //handle error     }     printf("socket created\n");      //prepare sockaddr_in structure     server.sin_family = af_inet;     server.sin_addr.s_addr = inaddr_any;     server.sin_port = htons( 8000 );      //binding, correctly.     if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server))< 0)     {         //error     }     printf("bind done");      //listen     listen(socket_desc , 3);      printf("waiting incoming connections...");     c = sizeof(struct sockaddr_in);       while( (client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)) )     {         puts("connection accepted");          pthread_t sniffer_thread;         new_sock = (int*) malloc(1);         *new_sock = client_sock;          if( pthread_create( &sniffer_thread , null ,  connection_handler , (void*) new_sock) < 0)         {             //error         }          printf("handler assigned");     }      if (client_sock < 0)     {         //error     }      //return 0;  }  /*  * handle connection each client may have , read indefinitely  * */ void *connection_handler(void *socket_desc) {     //get socket descriptor     int sock = *(int*)socket_desc;     int read_size;     char *message , client_message[2000];     string smatrix ;     int ind ;     string tok ;     int = 0 ;       //receive message client     while( (read_size = recv(sock , client_message , 2000 , 0)) > 0 )     {         //what want client's message     }      if(read_size == 0)     {         printf("client disconnected");         fflush(stdout);     }     else if(read_size == -1)     {         //error     }      //free socket pointer     free(socket_desc); 

as client, while loop until time has passed or given character or value entered. like:

while(wanttoexit == false){    char a;    printf("please enter char");    scanf("%c", &a);    write(sock , , 1); //note use strlen() strings } 

hope helps