#TCP \u5e76\u53d1；#\u591a\u8fdb\u7a0b；#\u591a\u7ebf\u7a0b；#\u7ebf\u7a0b\u6c60；#IO \u591a\u8def\u590d\u7528；#select；#epoll<\/p>\n
TCP \u534f\u8bae\u662f\u9762\u5411\u8fde\u63a5\u7684\u6d41\u5f0f\u4f20\u8f93\u534f\u8bae，\u57fa\u7840\u5355\u5faa\u73af TCP \u670d\u52a1\u5668\u903b\u8f91\u7b80\u5355：socket\u2192bind\u2192listen\u2192accept\u2192\u6536\u53d1\u6570\u636e\u2192close，\u4f46\u662faccept\u4e4b\u540e\u540c\u4e00\u65f6\u95f4\u53ea\u80fd\u5904\u7406\u4e00\u4e2a\u5ba2\u6237\u7aef\u8fde\u63a5，\u5f53\u7b2c\u4e8c\u4e2a\u5ba2\u6237\u7aef\u63a5\u5165\u65f6\u5fc5\u987b\u7b49\u5f85\u4e0a\u4e00\u4e2a\u5ba2\u6237\u7aef\u65ad\u5f00\u8fde\u63a5，\u670d\u52a1\u80fd\u529b\u4e25\u91cd\u53d7\u9650\u3002<\/p>\n
\u4e3a\u5b9e\u73b0\u4e00\u53f0\u670d\u52a1\u5668\u540c\u65f6\u548c\u591a\u4e2a\u5ba2\u6237\u7aef\u901a\u4fe1，\u9700\u8981\u6784\u5efaTCP \u5e76\u53d1\u670d\u52a1\u5668\u3002UDP \u672c\u8eab\u57fa\u4e8e\u65e0\u8fde\u63a5，recvfrom \u53ef\u4ee5\u76f4\u63a5\u63a5\u6536\u4efb\u610f\u5ba2\u6237\u7aef\u62a5\u6587，\u5929\u7136\u5177\u5907\u5e76\u53d1\u80fd\u529b；TCP \u9700\u8981\u989d\u5916\u5e76\u53d1\u6a21\u578b\u6765\u5904\u7406\u591a\u8def\u8fde\u63a5\u3002\u5e38\u89c1 4 \u79cd\u5b9e\u73b0\u65b9\u5f0f：\u591a\u8fdb\u7a0b\u6a21\u578b\u3001\u591a\u7ebf\u7a0b\u6a21\u578b\u3001\u7ebf\u7a0b\u6c60\u6a21\u578b\u3001IO \u591a\u8def\u590d\u7528\u6a21\u578b\u3002<\/p>\n
\u5355\u5faa\u73af\u670d\u52a1\u5668：\u670d\u52a1\u5668\u5904\u7406\u5b8c\u4e00\u4e2a\u5ba2\u6237\u7aef\u5168\u90e8\u901a\u4fe1，\u65ad\u5f00\u4e4b\u540e，\u624d\u4f1a\u518d\u6b21\u8c03\u7528accept\u63a5\u6536\u4e0b\u4e00\u4e2a\u5ba2\u6237\u7aef\u3002<\/p>\n
int sockfd = socket(AF_INET,SOCK_STREAM,0);
\nbind(sockfd,…);
\nlisten(sockfd,20);
\nwhile(1){
\n int connfd = accept(sockfd,NULL,NULL);
\n pid_t pid = fork();
\n if(pid > 0){
\n \/\/\u7236\u8fdb\u7a0b
\n close(connfd);
\n }else if(pid == 0){
\n \/\/\u5b50\u8fdb\u7a0b，\u5904\u7406\u5ba2\u6237\u7aef\u4e1a\u52a1
\n close(sockfd);
\n while(1){
\n recv(connfd,buf,sizeof(buf),0);
\n send(connfd,buf,len,0);
\n }
\n close(connfd);
\n exit(0);
\n }
\n}<\/p>\n
\u2705\u4f18\u70b9：\u8fdb\u7a0b\u4e4b\u95f4\u8d44\u6e90\u5b8c\u5168\u9694\u79bb，\u4e00\u4e2a\u5ba2\u6237\u7aef\u5f02\u5e38\u5d29\u6e83\u4e0d\u4f1a\u5f71\u54cd\u5176\u4ed6\u5ba2\u6237\u7aef；\u7a33\u5b9a\u6027\u9ad8\u3002 \u274c\u7f3a\u70b9：<\/p>\n
void *client_handle(void *arg){
\n int connfd = *(int*)arg;
\n free(arg);
\n char buf[1024]={0};
\n while(1){
\n recv(connfd,buf,sizeof(buf),0);
\n send(connfd,buf,strlen(buf),0);
\n }
\n close(connfd);
\n pthread_exit(NULL);
\n}<\/p>\n
int main(void){
\n int sockfd = socket(AF_INET,SOCK_STREAM,0);
\n bind(sockfd,…);
\n listen(sockfd,20);
\n while(1){
\n int *pfd = malloc(sizeof(int));
\n *pfd = accept(sockfd,NULL,NULL);
\n pthread_t tid;
\n pthread_create(&tid,NULL,client_handle,pfd);
\n pthread_detach(tid); \/\/\u8bbe\u7f6e\u5206\u79bb\u5c5e\u6027
\n }
\n return 0;
\n}<\/p>\n
\u2705\u4f18\u70b9：<\/p>\n
\u591a\u7ebf\u7a0b\u6a21\u578b\u6bcf\u5f53\u5ba2\u6237\u7aef\u8fde\u63a5\u5230\u6765\u5c31\u521b\u5efa\u7ebf\u7a0b，\u5ba2\u6237\u7aef\u65ad\u5f00\u9500\u6bc1\u7ebf\u7a0b\u3002\u9ad8\u9891\u8fde\u63a5\u573a\u666f，\u9891\u7e41\u521b\u5efa\u9500\u6bc1\u7ebf\u7a0b\u4f1a\u5e26\u6765 CPU \u5f00\u9500\u3002<\/p>\n
\u7ebf\u7a0b\u6c60：\u751f\u4ea7\u8005\u2011\u6d88\u8d39\u8005\u6a21\u5f0f\u3002<\/p>\n
\u2705\u4f18\u70b9：\u7ebf\u7a0b\u9884\u5148\u521b\u5efa，\u907f\u514d\u9891\u7e41\u521b\u5efa\u9500\u6bc1\u7ebf\u7a0b\u7684\u5f00\u9500；\u53ef\u63a7\u5236\u6700\u5927\u5e76\u53d1\u7ebf\u7a0b\u6570\u91cf，\u9632\u6b62\u7cfb\u7edf\u8d44\u6e90\u8017\u5c3d\u3002 \u274c\u7f3a\u70b9：\u9700\u8981\u5b9e\u73b0\u7ebf\u7a0b\u5b89\u5168\u7684\u4efb\u52a1\u961f\u5217，\u9700\u8981\u4e92\u65a5\u9501\u3001\u6761\u4ef6\u53d8\u91cf\u5b8c\u6210\u961f\u5217\u540c\u6b65，\u4ee3\u7801\u903b\u8f91\u590d\u6742\u3002<\/p>\n
IO \u591a\u8def\u590d\u7528：\u5355\u4e2a\u8fdb\u7a0b \/ \u7ebf\u7a0b，\u4e0d\u521b\u5efa\u8fdb\u7a0b\u3001\u7ebf\u7a0b，\u7531\u5185\u6838\u540c\u65f6\u76d1\u89c6\u591a\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26 IO \u4e8b\u4ef6（\u8bfb\u3001\u5199\u3001\u5f02\u5e38）\u3002 \u5f53\u67d0\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u53d1\u751f\u53ef\u8bfb \/ \u53ef\u5199\u4e8b\u4ef6，\u5185\u6838\u901a\u77e5\u5e94\u7528\u7a0b\u5e8f，\u5e94\u7528\u7a0b\u5e8f\u518d\u53bb\u6267\u884c\u8bfb\u5199\u64cd\u4f5c\u3002 \u76d1\u89c6\u5bf9\u8c61\u5305\u542b：\u76d1\u542c\u5957\u63a5\u5b57sockfd\u3001\u5404\u4e2a\u5ba2\u6237\u7aef\u901a\u4fe1\u5957\u63a5\u5b57connfd\u3002<\/p>\n
select\u5c06\u5f85\u76d1\u6d4b\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\u96c6\u5408\u4f20\u9012\u7ed9\u5185\u6838，\u5185\u6838\u963b\u585e\u7b49\u5f85，\u5f53\u96c6\u5408\u4e2d\u4efb\u610f fd \u53d1\u751f IO \u4e8b\u4ef6，\u8fd4\u56de\u5c31\u7eea\u4e8b\u4ef6\u6570\u91cf；\u7528\u6237\u6001\u904d\u5386\u96c6\u5408\u5224\u65ad\u54ea\u4e2a fd \u5c31\u7eea\u3002<\/p>\n
\u5173\u952e\u5b8f：<\/p>\n
\u51fd\u6570\u539f\u578b：<\/p>\n
int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout);<\/p>\n
\u53c2\u6570\u8bf4\u660e：<\/p>\n
\u8fd4\u56de\u503c：\u5c31\u7eea\u4e8b\u4ef6 fd \u7684\u4e2a\u6570；\u8d85\u65f6\u8fd4\u56de 0；\u51fa\u9519\u8fd4\u56de\u20111\u3002<\/p>\n
select \u5b58\u5728\u6587\u4ef6\u63cf\u8ff0\u7b26\u6570\u91cf\u4e0a\u9650\u9650\u5236，poll \u4f18\u5316\u8be5\u95ee\u9898，\u4f7f\u7528\u6570\u7ec4\u4fdd\u5b58\u5f85\u76d1\u63a7 fd，\u539f\u7406\u548c select \u7c7b\u4f3c\u3002<\/p>\n
Linux \u72ec\u6709 IO \u591a\u8def\u590d\u7528，\u6027\u80fd\u6700\u4f18，\u9002\u5408\u9ad8\u5e76\u53d1\u5927\u91cf\u8fde\u63a5\u573a\u666f\u3002 \u5de5\u4f5c\u6d41\u7a0b：<\/p>\n
\u2705\u4f18\u70b9：\u65e0\u9700\u5927\u91cf\u521b\u5efa\u8fdb\u7a0b\u7ebf\u7a0b，\u5185\u5b58\u5360\u7528\u4f4e，\u5355\u673a\u53ef\u4ee5\u652f\u6491\u4e0a\u4e07\u5e76\u53d1\u8fde\u63a5； \u274c\u7f3a\u70b9：\u7f16\u7a0b\u903b\u8f91\u590d\u6742；select \u6709 fd \u4e0a\u9650；epoll \u5c5e\u4e8e Linux \u5e73\u53f0\u7279\u6709，\u53ef\u79fb\u690d\u6027\u5dee\u3002<\/p>\n
\u8868\u683c<\/p>\n
| \u591a\u8fdb\u7a0b<\/td>\n | \u9ad8<\/td>\n | \u5f3a<\/td>\n | \u4f4e<\/td>\n | \u8fde\u63a5\u6570\u5c11，\u8ffd\u6c42\u7a33\u5b9a<\/td>\n<\/tr>\n |
| \u591a\u7ebf\u7a0b<\/td>\n | \u4e2d<\/td>\n | \u5f31<\/td>\n | \u4e2d<\/td>\n | \u4e2d\u7b49\u5e76\u53d1\u4e1a\u52a1<\/td>\n<\/tr>\n |
| \u7ebf\u7a0b\u6c60<\/td>\n | \u4e2d<\/td>\n | \u5f31<\/td>\n | \u4e2d<\/td>\n | \u8fde\u63a5\u9891\u7e41\u521b\u5efa\u9500\u6bc1\u573a\u666f<\/td>\n<\/tr>\n |
| IO \u591a\u8def\u590d\u7528 epoll<\/td>\n | \u6781\u4f4e<\/td>\n | \u65e0<\/td>\n | \u6781\u9ad8<\/td>\n | \u9ad8\u5e76\u53d1\u670d\u52a1\u5668<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n \u8865\u5145：UDP \u901a\u4fe1\u5929\u7136\u5e76\u53d1，\u4e0d\u9700\u8981\u4ee5\u4e0a\u5e76\u53d1\u6a21\u578b；TCP \u9762\u5411\u8fde\u63a5，\u6bcf\u4e00\u4e2a\u5ba2\u6237\u7aef\u5bf9\u5e94\u4e00\u4e2a connfd，\u5fc5\u987b\u501f\u52a9\u4e0a\u9762\u6a21\u578b\u5b9e\u73b0\u591a\u5ba2\u6237\u7aef\u540c\u65f6\u670d\u52a1\u3002<\/p>\n","protected":false},"excerpt":{"rendered":" #TCP \u5e76\u53d1；#\u591a\u8fdb\u7a0b；#\u591a\u7ebf\u7a0b；#\u7ebf\u7a0b\u6c60；#IO \u591a\u8def\u590d\u7528；#select；#epoll\u524d\u8a00TCP \u534f\u8bae\u662f\u9762\u5411\u8fde\u63a5\u7684\u6d41\u5f0f\u4f20\u8f93\u534f\u8bae，\u57fa\u7840\u5355\u5faa\u73af TCP \u670d\u52a1\u5668\u903b\u8f91\u7b80\u5355：socket\u2192bind\u2192listen\u2192accept\u2192\u6536\u53d1\u6570\u636e\u2192close，\u4f46\u662faccept\u4e4b\u540e\u540c\u4e00\u65f6\u95f4\u53ea\u80fd\u5904\u7406\u4e00\u4e2a\u5ba2\u6237\u7aef\u8fde\u63a5，\u5f53\u7b2c\u4e8c\u4e2a\u5ba2\u6237\u7aef\u63a5\u5165\u65f6\u5fc5\u987b\u7b49\u5f85\u4e0a\u4e00\u4e2a\u5ba2\u6237\u7aef\u65ad\u5f00<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[58,205,43],"topic":[],"class_list":["post-100039","post","type-post","status-publish","format-standard","hentry","category-server","tag-linux","tag-tcp-ip","tag-43"],"yoast_head":"\n |