c언어 소켓 통신 예제 (멀티 스레드, 멀티 프로세스)

멀티 스레드와 멀티 프로세스의 차이점을 설명한 글입니다.

요약하자면, 가장 큰 차이는 멀티스레드 방식은 공유 메모리를 갖고, 멀티프로세스 방식은 별도 메모리를 갖는듯..

내용을 확인 하신 후 상황에 맞는 소켓을 작성 하시기 바랍니다.

https://you9010.tistory.com/136

 

예제는 해외 사이트에서 가져왔으나, client 수 제한이 없거나 좀비프로세스 발생을 원치 않는다면 아래 URL 에서도 깔끔한 소스를 보실 수 있습니다.

https://velog.io/@jyongk/Multi-Process-Server-Multi-Thread-Server

 

 

멀티 스레드 방식

socket_server.c

 

#include <stdio.h> #include <stdlib.h> #include <sys/socket.h> #include <netinet/in.h> #include <string.h> #include <arpa/inet.h> #include <fcntl.h> // for open #include <unistd.h> // for close #include <pthread.h>   char client_message[2000]; char buffer[1024]; pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;   void * socketThread(void *arg) {   int newSocket = *((int *)arg);   recv(newSocket , client_message , 2000 , 0);     // Send message to the client socket    pthread_mutex_lock(&lock);   char *message = malloc(sizeof(client_message)+20);   strcpy(message,"Hello Client : ");   strcat(message,client_message);   strcat(message,"\n");   strcpy(buffer,message);   free(message);   pthread_mutex_unlock(&lock);   sleep(1);   send(newSocket,buffer,13,0);   printf("Exit socketThread \n");   close(newSocket);   pthread_exit(NULL); }   int main(){   int serverSocket, newSocket;   struct sockaddr_in serverAddr;   struct sockaddr_storage serverStorage;   socklen_t addr_size;     //Create the socket.    serverSocket = socket(PF_INET, SOCK_STREAM, 0);     // Configure settings of the server address struct   // Address family = Internet    serverAddr.sin_family = AF_INET;     //Set port number, using htons function to use proper byte order    serverAddr.sin_port = htons(7799);     //Set IP address to localhost    serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");       //Set all bits of the padding field to 0    memset(serverAddr.sin_zero, '\0', sizeof serverAddr.sin_zero);     //Bind the address struct to the socket    bind(serverSocket, (struct sockaddr *) &serverAddr, sizeof(serverAddr));     //Listen on the socket, with 40 max connection requests queued    if(listen(serverSocket,50)==0)     printf("Listening\n");   else     printf("Error\n");     pthread_t tid[60];     int i = 0;     while(1)     {         //Accept call creates a new socket for the incoming connection         addr_size = sizeof serverStorage;         newSocket = accept(serverSocket, (struct sockaddr *) &serverStorage, &addr_size);           //for each client request creates a thread and assign the client request to it to process        //so the main thread can entertain next request         if( pthread_create(&tid[i++], NULL, socketThread, &newSocket) != 0 )            printf("Failed to create thread\n");           if( i >= 50)         {           i = 0;           while(i < 50)           {             pthread_join(tid[i++],NULL);           }           i = 0;         }     }   return 0; }

 

멀티프로세스 방식

socket_server.c

 

#include <stdio.h> #include <stdlib.h> #include <sys/socket.h> #include <netinet/in.h> #include <string.h> #include <arpa/inet.h> #include <fcntl.h> // for open #include <unistd.h> // for close #include <sys/types.h> #include <pthread.h> pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;   void  socketThread(int clientSocket) {     char client_message[2000];   char buffer[1024];     int newSocket = clientSocket;     recv(newSocket , client_message , 2000 , 0);     // Send message to the client socket   pthread_mutex_lock(&lock);   char *message = malloc(sizeof(client_message)+20);   strcpy(message,"Hello Client : ");   strcat(message,client_message);   strcat(message,"\n");   strcpy(buffer,message);   free(message);   pthread_mutex_unlock(&lock);   sleep(1);   send(newSocket,buffer,13,0);   printf("Exit socketThread \n");   close(newSocket);   }       int main(){   int serverSocket, newSocket;   struct sockaddr_in serverAddr;   struct sockaddr_storage serverStorage;   socklen_t addr_size;   pid_t pid[50];   //Create the socket.   serverSocket = socket(PF_INET, SOCK_STREAM, 0);     // Configure settings of the server address struct   // Address family = Internet   serverAddr.sin_family = AF_INET;     //Set port number, using htons function to use proper byte order   serverAddr.sin_port = htons(7799);     //Set IP address to localhost   serverAddr.sin_addr.s_addr = inet_addr("0.0.0.0");   //Set all bits of the padding field to 0   memset(serverAddr.sin_zero, '\0', sizeof serverAddr.sin_zero);     //Bind the address struct to the socket   bind(serverSocket, (struct sockaddr *) &serverAddr, sizeof(serverAddr));     //Listen on the socket, with 50 max connection requests queued   if(listen(serverSocket,50)==0)     printf("Listening\n");   else     printf("Error\n");     int i = 0; while(1)     {         /* Accept call creates a new socket for the incoming connection */         addr_size = sizeof serverStorage;         newSocket = accept(serverSocket, (struct sockaddr *) &serverStorage, &addr_size);         int pid_c = 0;         if ((pid_c = fork())==0)         {           socketThread(newSocket);         }         else         {           pid[i++] = pid_c;           if( i >= 49)            {              i = 0;              while(i < 50)                 waitpid(pid[i++], NULL, 0);              i = 0;            }         }     }   return 0; }

클라이언트 소켓 파일

socket_client.c

 

#include <stdio.h> #include <sys/socket.h> #include <netinet/in.h> #include <string.h> #include <arpa/inet.h> #include <stdlib.h> #include <fcntl.h> // for open #include <unistd.h> // for close #include<pthread.h>   void * cientThread(void *arg) {   printf("In thread\n");   char message[1000];   char buffer[1024];   int clientSocket;   struct sockaddr_in serverAddr;   socklen_t addr_size;     // Create the socket.    clientSocket = socket(PF_INET, SOCK_STREAM, 0);     //Configure settings of the server address  // Address family is Internet    serverAddr.sin_family = AF_INET;     //Set port number, using htons function    serverAddr.sin_port = htons(7799);    //Set IP address to localhost   serverAddr.sin_addr.s_addr = inet_addr("localhost");   memset(serverAddr.sin_zero, '\0', sizeof serverAddr.sin_zero);       //Connect the socket to the server using the address     addr_size = sizeof serverAddr;     connect(clientSocket, (struct sockaddr *) &serverAddr, addr_size);     strcpy(message,"Hello");      if( send(clientSocket , message , strlen(message) , 0) < 0)     {             printf("Send failed\n");     }       //Read the message from the server into the buffer     if(recv(clientSocket, buffer, 1024, 0) < 0)     {        printf("Receive failed\n");     }     //Print the received message     printf("Data received: %s\n",buffer);     close(clientSocket);     pthread_exit(NULL); } int main(){   int i = 0;   pthread_t tid[51];   while(i< 50)   {     if( pthread_create(&tid[i], NULL, cientThread, NULL) != 0 )            printf("Failed to create thread\n");     i++;   }   sleep(20);   i = 0;   while(i< 50)   {      pthread_join(tid[i++],NULL);      printf("%d:\n",i);   }   return 0; }

 

 

 

[출처] https://dzone.com/articles/parallel-tcpip-socket-server-with-multi-threading

[수정] 출처의 예제에 오타가 있어서 바로 실행하면 에러가 발생합니다. 소스를 보완하여 작성하였습니다.