[TOC] # 简介 在使用线程模型开发服务器时需考虑以下问题： 1. 调整进程内最大文件描述符上限 2. 线程如有共享数据，考虑线程同步 3. 服务于客户端线程退出时，退出处理。（退出值，分离态） 4. 系统负载，随着链接客户端增加，导致其它线程不能及时得到CPU # server ~~~ /* server.c */ #include <stdio.h> #include <string.h> #include <netinet/in.h> #include <arpa/inet.h> #include <pthread.h> #include "wrap.h" #define MAXLINE 80 #define SERV_PORT 6666 struct s_info { struct sockaddr_in cliaddr; int connfd; }; void *do_work(void *arg) { int n,i; struct s_info *ts = (struct s_info*)arg; char buf[MAXLINE]; char str[INET_ADDRSTRLEN]; /* 可以在创建线程前设置线程创建属性,设为分离态,哪种效率高呢？ */ pthread_detach(pthread_self()); while (1) { n = Read(ts->connfd, buf, MAXLINE); if (n == 0) { printf("the other side has been closed.\n"); break; } printf("received from %s at PORT %d\n", inet_ntop(AF_INET, &(*ts).cliaddr.sin_addr, str, sizeof(str)), ntohs((*ts).cliaddr.sin_port)); for (i = 0; i < n; i++) buf[i] = toupper(buf[i]); Write(ts->connfd, buf, n); } Close(ts->connfd); } int main(void) { struct sockaddr_in servaddr, cliaddr; socklen_t cliaddr_len; int listenfd, connfd; int i = 0; pthread_t tid; struct s_info ts[256]; listenfd = Socket(AF_INET, SOCK_STREAM, 0); bzero(&servaddr, sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_addr.s_addr = htonl(INADDR_ANY); servaddr.sin_port = htons(SERV_PORT); Bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)); Listen(listenfd, 20); printf("Accepting connections ...\n"); while (1) { cliaddr_len = sizeof(cliaddr); connfd = Accept(listenfd, (struct sockaddr *)&cliaddr, &cliaddr_len); ts[i].cliaddr = cliaddr; ts[i].connfd = connfd; /* 达到线程最大数时，pthread_create出错处理, 增加服务器稳定性 */ pthread_create(&tid, NULL, do_work, (void*)&ts[i]); i++; } return 0; } ~~~ # client ~~~ /* client.c */ #include <stdio.h> #include <string.h> #include <unistd.h> #include <netinet/in.h> #include "wrap.h" #define MAXLINE 80 #define SERV_PORT 6666 int main(int argc, char *argv[]) { struct sockaddr_in servaddr; char buf[MAXLINE]; int sockfd, n; sockfd = Socket(AF_INET, SOCK_STREAM, 0); bzero(&servaddr, sizeof(servaddr)); servaddr.sin_family = AF_INET; inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr); servaddr.sin_port = htons(SERV_PORT); Connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)); while (fgets(buf, MAXLINE, stdin) != NULL) { Write(sockfd, buf, strlen(buf)); n = Read(sockfd, buf, MAXLINE); if (n == 0) printf("the other side has been closed.\n"); else Write(STDOUT_FILENO, buf, n); } Close(sockfd); return 0; } ~~~