APUE学习笔记——socket通信 阻塞IO

服务器端：

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <error.h>#include <errno.h>#include <sys/socket.h>#include <netinet/in.h>#include <sys/types.h>#include <unistd.h>#define BACKLOG 10int main(){    struct sockaddr_in server_sockaddr,client_sockaddr;    int sockfd,clientfd;    socklen_t clientsize;        server_sockaddr.sin_family = AF_INET;    server_sockaddr.sin_port = htons(9000);    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);    bzero(&(server_sockaddr.sin_zero),8);        if((sockfd = socket(AF_INET,SOCK_STREAM,0)) == -1){        perror("socket() error");        exit(-1);    }        if(bind(sockfd,(struct sockaddr *)&server_sockaddr,sizeof(struct sockaddr)) == -1){        perror("bind() error");        exit(-1);    }        if(listen(sockfd,BACKLOG) == -1){        perror("listen() error");        exit(-1);    }        pid_t pid;    ssize_t recvsize,sendsize;    char buf[128];    while(1){        clientsize = sizeof(struct sockaddr);        if((clientfd = accept(sockfd,(struct sockaddr*)&client_sockaddr,&clientsize)) == -1){            perror("accept() error");            exit(-1);        }        pid = fork();        if(pid == 0){            close(sockfd);            while(1){                if((recvsize = recv(clientfd,buf,sizeof(buf),0)) == -1){                    perror("recv() error");                    exit(-1);                }                if(recvsize == 0 || strncmp(buf,"quit",4) == 0)                     exit(0);//child process exit                printf("Received: %s",buf);                bzero(buf,0);                printf("Input message to send client: ");                fgets(buf,128,stdin);                if((sendsize = send(clientfd,buf,sizeof(buf),0)) == -1){                    perror("send() error");                    exit(-1);                }            }        }    }    close(sockfd);    return 0;}

客户端：

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <error.h>#include <errno.h>#include <sys/socket.h>#include <netinet/in.h>#include <sys/types.h>#include <unistd.h>#include <arpa/inet.h>int main(){    struct sockaddr_in server_addr;    int sockfd;        if((sockfd = socket(AF_INET,SOCK_STREAM,0)) == -1){        perror("socket() error");        exit(-1);    }            server_addr.sin_family = AF_INET;    server_addr.sin_port = htons(9000);    inet_pton(AF_INET,"127.0.0.1",&server_addr.sin_addr);    bzero(&(server_addr.sin_zero),8);        if(connect(sockfd,(struct sockaddr*)&server_addr,sizeof(struct sockaddr)) == -1){        perror("connect() error");        exit(-1);    }    ssize_t sendsize,recvsize;    char buf[128];    while(1){        printf("Input message to send server: ");        bzero(buf,0);        fgets(buf,128,stdin);        if((sendsize = send(sockfd,buf,sizeof(buf),0)) == -1){            perror("send() error");            exit(-1);        }        if(sendsize == 0 || strncmp(buf,"quit",4) == 0)             break;        bzero(buf,0);        if((recvsize = recv(sockfd,buf,sizeof(buf),0)) == -1){            perror("recv() error");            exit(-1);        }        printf("Received: %s",buf);    }    close(sockfd);    return 0;}

简单说明：客户端就是循环与服务端通信没啥可以解释的，服务端使用while循环来accept多个客户端的访问请求，但具体的通信操作交给子进程，父进程只负责监听客户端的请求。具体例子参考UNIX网络编程（套接字）