linux 下 tcp server 的 demo

#include<stdio.h>#include<string.h>#include<stdlib.h>#include<unistd.h>#include<sys/socket.h>#include<sys/types.h>#include<netdb.h>#include<arpa/inet.h>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[]){// Variables for writing a server. /*1. Getting the address data structure.2. Openning a new socket.3. Bind to the socket.4. Listen to the socket. 5. Accept Connection.6. Receive Data.7. Close Connection. */int status;struct addrinfo hints, * res;int listner; // Before using hint you have to make sure that the data structure is empty memset(& hints, 0, sizeof hints);// Set the attribute for hinthints.ai_family = AF_UNSPEC; // We don't care V4 AF_INET or 6 AF_INET6hints.ai_socktype = SOCK_STREAM; // TCP Socket SOCK_DGRAM hints.ai_flags = AI_PASSIVE; // Fill the res data structure and make sure that the results make sense. char sever_port_default[100]="6666";char * p_sever_port = NULL;if(argc>=2)p_sever_port = argv[1];elsep_sever_port = sever_port_default;printf("Sever port:%s\n",p_sever_port);//status = getaddrinfo(NULL, "6666", &hints, &res);status = getaddrinfo(NULL, p_sever_port , &hints, &res);if(status != 0){fprintf(stderr,"getaddrinfo error: %s\n",gai_strerror(status));}// Create Socket and check if error occured afterwardslistner = socket(res->ai_family,res->ai_socktype, res->ai_protocol);if(listner < 0 ){fprintf(stderr,"socket error: %s\n",gai_strerror(status));}// Bind the socket to the address of my local machine and port number status = bind(listner, res->ai_addr, res->ai_addrlen); if(status < 0){fprintf(stderr,"bind: %s\n",gai_strerror(status));}status = listen(listner, 10); if(status < 0){fprintf(stderr,"listen: %s\n",gai_strerror(status));}// Free the res linked list after we are done with itfreeaddrinfo(res);// We should wait now for a connection to acceptint new_conn_fd;struct sockaddr_storage client_addr;socklen_t addr_size;char s[INET6_ADDRSTRLEN]; // an empty string // Calculate the size of the data structureaddr_size = sizeof client_addr;printf("I am now accepting connections ...\n");while(1){// Accept a new connection and return back the socket desciptor new_conn_fd = accept(listner, (struct sockaddr *) & client_addr, &addr_size);if(new_conn_fd < 0){fprintf(stderr,"accept: %s\n",gai_strerror(new_conn_fd));continue;}inet_ntop(client_addr.ss_family, get_in_addr((struct sockaddr *) &client_addr),s ,sizeof s); printf("I am now connected to %s \n",s);status = send(new_conn_fd,"Welcome", 7,0);if(status == -1){close(new_conn_fd);_exit(4);}}// Close the socket before we finish close(new_conn_fd);return 0;}

参考链接：http://code.runnable.com/VXjZZimG7Nk0smWF/simple-tcp-server-code-for-c%2B%2B-and-socket