我试图通过服务器在2个客户端之间建立连接。在此程序中，客户端向服务器发送消息，服务器将其发布到目标客户端。但是这个操作之间有一点问题。发送器在接收到一些消息之前不能发送另一个消息，或者在发送消息之前无法看到接收到的消息。视频应该更好地解释。
您可以在client.c代码
下面找到scanf函数
//
// Created by berkin on 18.12.2016.
//
#include<stdio.h>
#include<sys/socket.h>
#include<arpa/inet.h> // for inet_addr
#include <string.h>
#include <zconf.h>
int main(int argc, char *argv[]) {
int sock;
struct sockaddr_in server;
char message[2000], server_reply[2000];
//Create socket
sock = socket(AF_INET, SOCK_STREAM, 0);
if (sock == -1) {
printf("Could not create socket");
}
server.sin_addr.s_addr = inet_addr("127.0.0.1");
server.sin_family = AF_INET;
server.sin_port = htons(8888);
//Connect to remote server
if (connect(sock, (struct sockaddr *) &server, sizeof(server)) < 0) {
perror("Connect failed. Error");
return 1;
}
puts("Connected to server\n");
//keep communicating with server
while (1) {
printf("> ");
scanf("%[^\n]%*c", message);
fflush(stdin);
//Send some data
if (send(sock, message, strlen(message)+1, 0) < 0) {
puts("Send failed");
return 1;
}
if (recv(sock, server_reply, 2000, 0) < 0) {
puts("recv failed");
break;
}
//Receive a reply from the server
printf ("\033[32;1m %s \033[0m\n",server_reply);
}
close(sock);
return 0;
}
#include<stdio.h>
#include<string.h> // for strlen
#include<stdlib.h>
#include<sys/socket.h>
#include<arpa/inet.h> // for inet_addr
#include<unistd.h> // for write
#include<pthread.h> // for threading, link with lpthread
#include "split.h"
#define MAX_CLIENT_NUMBER 100
void *connection_handler(void *);
struct User {
char userName[10];
int clientSocketNo;
};
unsigned int clientNumber = 0;
unsigned int userArrayIndex = 0;
struct User users[MAX_CLIENT_NUMBER];
//FOR GETUSERS COMMAND
void getUsers(int socketNumber) {
char *userString = malloc(100);
if (users[0].userName != NULL) {
strcpy(userString, users[0].userName);
strcat(userString, ",");
} else {
return;
}
for (int i = 1; i < userArrayIndex; ++i) {
strcat(userString, users[i].userName);
strcat(userString, ",");
}
write(socketNumber, userString, strlen(userString) + 1);
}
//AFTER LOGIN COMMAND, ADD TO THE ARRAY
void addUserToArray(char userName[10], int socketNumber) {
printf("Client logged in as %s\n", userName);
strcpy(users[userArrayIndex].userName, userName);
users[userArrayIndex].clientSocketNo = socketNumber;
userArrayIndex++;
}
//LOGIN COMMAND
void loginUser(char userName[10], int socketNumber) {
char *message = "login successful";
write(socketNumber, message, strlen(message) + 1);
addUserToArray(userName, socketNumber);
}
//SEND MESSAGE IF USER FOUND
void sendMessage(struct User user, char *message){
write(user.clientSocketNo,message,strlen(message) + 1);
}
//SEARCH USER FROM ARRAY
struct User searchUser(char searchName[10]){
for (int i = 0; i < userArrayIndex; ++i) {
if(strcmp(users[i].userName,searchName) == 0){
return users[i];
}
}
}
void *connection_handler(void *socket_desc) {
//Get the socket descriptor
char receivedMessage[2000]; //client's message
int readControl;
int parsedItemNumber = 0;
int sock = *((int *) socket_desc);
while ((readControl = recv(sock, receivedMessage, 2000, 0)) > 0) {
char *parsedCommand[50]; //parsedClientMessage
parsedItemNumber = parsing(parsedCommand, receivedMessage, " ");
if (strcmp(parsedCommand[0], "login") == 0) {
loginUser(parsedCommand[1], sock);
}
else if (strcmp(parsedCommand[0], "getusers") == 0) {
getUsers(sock);
}
else if (strcmp(parsedCommand[0], "exit") == 0) {
close(sock);
return 0;
}
else{
if(parsedCommand[0] != NULL){
struct User find = searchUser(parsedCommand[0]);
if(find.userName != NULL){
char *message = malloc(2000);
if(parsedCommand[1] != NULL){
strcpy(message,parsedCommand[1]);
strcat(message," ");
}
for (int i = 2; i < parsedItemNumber; ++i) {
strcat(message,parsedCommand[i]);
strcat(message," ");
}
sendMessage(find,message);
}
else{
perror("Your input was wrong");
}
}
}
}
if (readControl == 0) {
puts("Client disconnected");
clientNumber--;
fflush(stdout);
} else if (readControl == -1) {
perror("recv failed");
}
//Free the socket pointer
free(socket_desc);
return 0;
}
int main(int argc, char *argv[]) {
int socket_desc, new_socket, c, *new_sock;
struct sockaddr_in server, client;
//Create Socket
socket_desc = socket(AF_INET, SOCK_STREAM, 0);
if (socket_desc == -1) {
puts("Could not create socket");
return 1;
}
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons(8888);
if (bind(socket_desc, (struct sockaddr *) &server, sizeof(server)) < 0) {
puts("Binding failed");
return 1;
}
listen(socket_desc, 3);
puts("Server started");
c = sizeof(struct sockaddr_in);
while ((new_socket = accept(socket_desc, (struct sockaddr *) &client, (socklen_t *) &c)) &&
clientNumber < MAX_CLIENT_NUMBER) {
pthread_t sniffer_thread[MAX_CLIENT_NUMBER];
new_sock = malloc(1);
*new_sock = new_socket;
if (pthread_create(&sniffer_thread[clientNumber], NULL, connection_handler,
(void *) new_sock) < 0) {
perror("Could not create thread");
return 1;
} else {
clientNumber++;
}
puts("Client connected");
}
if (new_socket < 0) {
perror("accept failed");
return 1;
}
return 0;
}