\u6211\u8ba9deepseek\u5199\u4e86\u4e00\u4e2a\u7a0b\u5e8f，\u7ed3\u679c\u6211\u7adf\u7136\u6709\u597d\u591a\u770b\u4e0d\u660e\u767d\u7684\u6280\u5de7，\u6cea\u6d41\u6ee1\u9762\u4e86\u3002<\/p>\n
\u5df2\u6df1\u5ea6\u601d\u8003（\u7528\u65f6 95 \u79d2）<\/p>\n
\u597d\u7684，\u6211\u73b0\u5728\u9700\u8981\u5199\u4e00\u4e2aLinux\u4e0b\u7684TCP\u670d\u52a1\u5668\u7a0b\u5e8f，\u529f\u80fd\u662f\u5c06\u6536\u5230\u7684\u6570\u636e\u539f\u8def\u8fd4\u56de\u3002\u4e5f\u5c31\u662f\u6240\u8c13\u7684\u56de\u663e\u670d\u52a1\u5668，Echo Server\u3002\u6211\u4e4b\u524d\u6ca1\u5199\u8fc7\u8fd9\u6837\u7684\u7a0b\u5e8f，\u4f46\u6709\u4e00\u4e9bC\u8bed\u8a00\u548c\u7f51\u7edc\u7f16\u7a0b\u7684\u57fa\u7840\u77e5\u8bc6，\u6240\u4ee5\u5f97\u4ed4\u7ec6\u60f3\u60f3\u8be5\u600e\u4e48\u5b9e\u73b0\u3002<\/p>\n<\/p>\n
\u9996\u5148，\u6211\u5e94\u8be5\u56de\u5fc6\u4e00\u4e0bTCP\u670d\u52a1\u5668\u7684\u5de5\u4f5c\u6d41\u7a0b\u3002\u4e00\u822c\u6765\u8bf4，TCP\u670d\u52a1\u5668\u7684\u6b65\u9aa4\u5927\u6982\u662f\u8fd9\u6837\u7684：\u521b\u5efa\u5957\u63a5\u5b57，\u7ed1\u5b9a\u5730\u5740\u548c\u7aef\u53e3，\u76d1\u542c\u8fde\u63a5，\u63a5\u53d7\u8fde\u63a5，\u7136\u540e\u5904\u7406\u6570\u636e\u3002\u5bf9\u5427？<\/p>\n<\/p>\n
\u90a3\u5177\u4f53\u5230\u6bcf\u4e2a\u6b65\u9aa4，\u5e94\u8be5\u600e\u4e48\u505a\u5462？\u9996\u5148，\u521b\u5efa\u5957\u63a5\u5b57\u3002\u4f7f\u7528socket()\u51fd\u6570，\u53c2\u6570\u5e94\u8be5\u662fAF_INET（IPv4），SOCK_STREAM（TCP），\u534f\u8bae\u53ef\u4ee5\u586b0，\u8ba9\u7cfb\u7edf\u81ea\u52a8\u9009\u62e9\u3002\u7136\u540e\u9700\u8981\u7ed1\u5b9a\u5730\u5740\u548c\u7aef\u53e3\u5230\u5957\u63a5\u5b57，\u8fd9\u9700\u8981\u8bbe\u7f6e\u4e00\u4e2asockaddr_in\u7ed3\u6784，\u5305\u62ec\u5730\u5740\u65cf\u3001\u7aef\u53e3\u53f7\u548cIP\u5730\u5740\u3002\u8fd9\u91cc\u670d\u52a1\u5668\u7684IP\u5730\u5740\u901a\u5e38\u7528INADDR_ANY，\u8868\u793a\u76d1\u542c\u6240\u6709\u53ef\u7528\u7684\u63a5\u53e3\u3002\u7ed1\u5b9a\u65f6\u7528bind()\u51fd\u6570\u3002<\/p>\n<\/p>\n
\u63a5\u7740\u662f\u76d1\u542c，\u7528listen()\u51fd\u6570，\u8bbe\u7f6e\u7b49\u5f85\u8fde\u63a5\u961f\u5217\u7684\u6700\u5927\u957f\u5ea6\u3002\u7136\u540e\u8fdb\u5165\u5faa\u73af，\u7528accept()\u63a5\u53d7\u5ba2\u6237\u7aef\u7684\u8fde\u63a5\u3002accept()\u4f1a\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684\u5957\u63a5\u5b57，\u7528\u4e8e\u548c\u5ba2\u6237\u7aef\u901a\u4fe1\u3002\u8fd9\u65f6\u5019，\u670d\u52a1\u5668\u901a\u5e38\u4f1afork\u4e00\u4e2a\u5b50\u8fdb\u7a0b\u6216\u8005\u521b\u5efa\u4e00\u4e2a\u7ebf\u7a0b\u6765\u5904\u7406\u8fd9\u4e2a\u8fde\u63a5，\u6216\u8005\u4f7f\u7528\u975e\u963b\u585e\u7684\u65b9\u5f0f，\u4f46\u8fd9\u91cc\u53ef\u80fd\u7b80\u5355\u5904\u7406，\u9010\u4e2a\u5904\u7406\u8fde\u63a5？\u4e0d\u8fc7\u8fd9\u6837\u7684\u8bdd，\u4e00\u6b21\u53ea\u80fd\u5904\u7406\u4e00\u4e2a\u5ba2\u6237\u7aef\u3002\u6216\u8005\u662f\u5426\u5e94\u8be5\u4f7f\u7528\u591a\u7ebf\u7a0b\u6216\u8005\u591a\u8fdb\u7a0b？\u6216\u8005\u53ef\u80fd\u4f8b\u5b50\u4e2d\u7528\u5355\u7ebf\u7a0b，\u9010\u4e2a\u5904\u7406，\u4f46\u8fd9\u6837\u53ef\u80fd\u4e0d\u591f\u5b9e\u7528\u3002\u4e0d\u8fc7\u5bf9\u4e8e\u7b80\u5355\u7684\u793a\u4f8b\u6765\u8bf4，\u53ef\u80fd\u53ef\u4ee5\u6682\u65f6\u4e0d\u8003\u8651\u5e76\u53d1，\u5148\u5904\u7406\u5355\u4e2a\u8fde\u63a5，\u7136\u540e\u518d\u4f18\u5316？<\/p>\n<\/p>\n
\u7136\u540e，\u5f53\u5ba2\u6237\u7aef\u8fde\u63a5\u540e，\u670d\u52a1\u5668\u9700\u8981\u8bfb\u53d6\u5ba2\u6237\u7aef\u53d1\u6765\u7684\u6570\u636e，\u7136\u540e\u5c06\u6570\u636e\u56de\u53d1\u56de\u53bb\u3002\u8fd9\u4e2a\u8fc7\u7a0b\u53ef\u80fd\u662f\u5728\u4e00\u4e2a\u5faa\u73af\u91cc，recv()\u8bfb\u53d6\u6570\u636e，\u7136\u540esend()\u53d1\u9001\u56de\u53bb\u3002\u76f4\u5230\u5ba2\u6237\u7aef\u5173\u95ed\u8fde\u63a5，\u8fd9\u65f6\u5019recv()\u8fd4\u56de0，\u6216\u8005\u51fa\u9519，\u7136\u540e\u5173\u95ed\u8fde\u63a5\u3002<\/p>\n<\/p>\n
\u90a3\u5177\u4f53\u5230\u4ee3\u7801\u7ed3\u6784，\u5927\u6982\u662f\u8fd9\u6837\u7684：<\/p>\n<\/p>\n
1. \u521b\u5efasocket：socket()<\/p>\n
2. \u8bbe\u7f6e\u5730\u5740\u7ed3\u6784：sockaddr_in，\u5305\u62ec\u7aef\u53e3\u53f7\u7b49\u3002<\/p>\n
3. bind()\u7ed1\u5b9a\u5730\u5740<\/p>\n
4. listen()\u5f00\u59cb\u76d1\u542c<\/p>\n
5. accept()\u63a5\u53d7\u8fde\u63a5，\u5f97\u5230\u65b0\u7684socket<\/p>\n
6. \u5faa\u73af：recv()\u63a5\u6536\u6570\u636e，send()\u53d1\u9001\u56de\u53bb<\/p>\n
7. \u5173\u95ed\u8fde\u63a5<\/p>\n<\/p>\n
\u4f46\u53ef\u80fd\u9047\u5230\u7684\u95ee\u9898\u662f，\u5982\u4f55\u5904\u7406\u591a\u4e2a\u5ba2\u6237\u7aef？\u6bd4\u5982，\u5f53\u4e00\u4e2a\u5ba2\u6237\u7aef\u5728\u5904\u7406\u7684\u65f6\u5019，\u5176\u4ed6\u5ba2\u6237\u7aef\u65e0\u6cd5\u8fde\u63a5\u3002\u6240\u4ee5\u53ef\u80fd\u5e94\u8be5\u6bcf\u63a5\u53d7\u5230\u4e00\u4e2a\u8fde\u63a5，\u5c31\u521b\u5efa\u4e00\u4e2a\u5b50\u8fdb\u7a0b\u6216\u8005\u7ebf\u7a0b\u6765\u5904\u7406\u3002\u6bd4\u5982，\u4f7f\u7528fork()\u521b\u5efa\u5b50\u8fdb\u7a0b，\u5728\u5b50\u8fdb\u7a0b\u4e2d\u5904\u7406\u6570\u636e\u6536\u53d1，\u800c\u4e3b\u8fdb\u7a0b\u7ee7\u7eed\u7b49\u5f85\u5176\u4ed6\u8fde\u63a5\u3002<\/p>\n<\/p>\n
\u8fd9\u6837，\u4e3b\u8fdb\u7a0b\u5728accept\u4e4b\u540efork，\u5b50\u8fdb\u7a0b\u5904\u7406\u5177\u4f53\u7684\u901a\u4fe1，\u7236\u8fdb\u7a0b\u5173\u95ed\u8fde\u63a5\u5957\u63a5\u5b57，\u7ee7\u7eed\u5faa\u73afaccept\u3002<\/p>\n<\/p>\n
\u4e0d\u8fc7\u9700\u8981\u6ce8\u610f，\u5b50\u8fdb\u7a0b\u9700\u8981\u6b63\u786e\u5173\u95ed\u4e0d\u9700\u8981\u7684\u5957\u63a5\u5b57，\u5426\u5219\u53ef\u80fd\u5bfc\u81f4\u8d44\u6e90\u6cc4\u9732\u3002\u6b64\u5916，\u8fd8\u9700\u8981\u5904\u7406\u50f5\u5c38\u8fdb\u7a0b\u7684\u95ee\u9898，\u901a\u8fc7signal(SIGCHLD, SIG_IGN)\u6765\u5ffd\u7565\u5b50\u8fdb\u7a0b\u7ed3\u675f\u4fe1\u53f7，\u6216\u8005\u4f7f\u7528waitpid()\u56de\u6536\u8d44\u6e90\u3002<\/p>\n<\/p>\n
\u90a3\u73b0\u5728，\u6211\u9700\u8981\u628a\u8fd9\u4e9b\u6b65\u9aa4\u8f6c\u5316\u4e3aC\u4ee3\u7801\u3002<\/p>\n<\/p>\n
\u9996\u5148，\u5934\u6587\u4ef6\u53ef\u80fd\u9700\u8981\u5305\u62ec：<\/p>\n<\/p>\n
#include <stdio.h><\/p>\n
#include <stdlib.h><\/p>\n
#include <string.h><\/p>\n
#include <unistd.h><\/p>\n
#include <sys\/types.h><\/p>\n
#include <sys\/socket.h><\/p>\n
#include <netinet\/in.h><\/p>\n
#include <arpa\/inet.h><\/p>\n<\/p>\n
\u7136\u540e，\u4e3b\u51fd\u6570\u7684\u7ed3\u6784：<\/p>\n<\/p>\n
int main() {<\/p>\n
int sockfd, newsockfd, portno;<\/p>\n
struct sockaddr_in serv_addr, cli_addr;<\/p>\n
socklen_t clilen;<\/p>\n
\/\/ \u521b\u5efasocket<\/p>\n
sockfd = socket(AF_INET, SOCK_STREAM, 0);<\/p>\n
if (sockfd < 0) {<\/p>\n
perror("ERROR opening socket");<\/p>\n
exit(1);<\/p>\n
}<\/p>\n
\/\/ \u8bbe\u7f6eserv_addr\u7ed3\u6784<\/p>\n
bzero((char *) &serv_addr, sizeof(serv_addr));<\/p>\n
portno = 12345; \/\/ \u5047\u8bbe\u7aef\u53e3\u53f7\u662f12345<\/p>\n
serv_addr.sin_family = AF_INET;<\/p>\n
serv_addr.sin_addr.s_addr = INADDR_ANY;<\/p>\n
serv_addr.sin_port = htons(portno);<\/p>\n
\/\/ bind<\/p>\n
if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {<\/p>\n
perror("ERROR on binding");<\/p>\n
exit(1);<\/p>\n
}<\/p>\n
\/\/ listen<\/p>\n
listen(sockfd, 5);<\/p>\n
clilen = sizeof(cli_addr);<\/p>\n
while (1) {<\/p>\n
\/\/ accept<\/p>\n
newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);<\/p>\n
if (newsockfd < 0) {<\/p>\n
perror("ERROR on accept");<\/p>\n
exit(1);<\/p>\n
}<\/p>\n
\/\/ fork\u5b50\u8fdb\u7a0b<\/p>\n
pid_t pid = fork();<\/p>\n
if (pid < 0) {<\/p>\n
perror("ERROR on fork");<\/p>\n
exit(1);<\/p>\n
}<\/p>\n
if (pid == 0) { \/\/ \u5b50\u8fdb\u7a0b<\/p>\n
close(sockfd); \/\/ \u5b50\u8fdb\u7a0b\u4e0d\u9700\u8981\u76d1\u542csocket<\/p>\n
\/\/ \u5904\u7406\u6570\u636e<\/p>\n
char buffer[256];<\/p>\n
int n;<\/p>\n
while (1) {<\/p>\n
n = recv(newsockfd, buffer, 255, 0);<\/p>\n
if (n < 0) {<\/p>\n
perror("ERROR reading from socket");<\/p>\n
break;<\/p>\n
} else if (n == 0) {<\/p>\n
\/\/ \u5ba2\u6237\u7aef\u5173\u95ed\u8fde\u63a5<\/p>\n
break;<\/p>\n
}<\/p>\n
\/\/ \u53d1\u9001\u56de\u53bb<\/p>\n
n = send(newsockfd, buffer, n, 0);<\/p>\n
if (n < 0) {<\/p>\n
perror("ERROR writing to socket");<\/p>\n
break;<\/p>\n
}<\/p>\n
}<\/p>\n
close(newsockfd);<\/p>\n
exit(0); \/\/ \u5b50\u8fdb\u7a0b\u7ed3\u675f<\/p>\n
} else { \/\/ \u7236\u8fdb\u7a0b<\/p>\n
close(newsockfd); \/\/ \u7236\u8fdb\u7a0b\u5173\u95ed\u8fde\u63a5\u5957\u63a5\u5b57<\/p>\n
}<\/p>\n
}<\/p>\n
close(sockfd);<\/p>\n
return 0;<\/p>\n
}<\/p>\n<\/p>\n
\u4e0d\u8fc7，\u8fd9\u91cc\u53ef\u80fd\u6709\u51e0\u4e2a\u95ee\u9898\u9700\u8981\u6ce8\u610f：<\/p>\n<\/p>\n
1. \u5b50\u8fdb\u7a0b\u7ed3\u675f\u540e\u4f1a\u6210\u4e3a\u50f5\u5c38\u8fdb\u7a0b，\u9700\u8981\u5904\u7406\u3002\u53ef\u4ee5\u901a\u8fc7signal(SIGCHLD, SIG_IGN)\u6765\u8ba9\u7cfb\u7edf\u81ea\u52a8\u56de\u6536，\u6216\u8005\u5728\u7236\u8fdb\u7a0b\u4e2d\u8c03\u7528waitpid\u3002<\/p>\n<\/p>\n
\u6240\u4ee5\u5e94\u8be5\u5728\u4e3b\u51fd\u6570\u5f00\u59cb\u65f6\u8bbe\u7f6e\u5ffd\u7565SIGCHLD\u4fe1\u53f7：<\/p>\n<\/p>\n
signal(SIGCHLD, SIG_IGN);<\/p>\n<\/p>\n
\u8fd9\u6837，\u5f53\u5b50\u8fdb\u7a0b\u7ed3\u675f\u65f6，\u7236\u8fdb\u7a0b\u4e0d\u4f1a\u79ef\u7d2f\u50f5\u5c38\u8fdb\u7a0b\u3002<\/p>\n<\/p>\n
2. \u9519\u8bef\u5904\u7406\u9700\u8981\u66f4\u5b8c\u5584\u3002\u6bd4\u5982，accept\u53ef\u80fd\u88ab\u4fe1\u53f7\u4e2d\u65ad，\u6240\u4ee5\u9700\u8981\u8003\u8651EINTR\u7684\u60c5\u51b5？\u4e0d\u8fc7\u5bf9\u4e8e\u7b80\u5355\u793a\u4f8b\u53ef\u80fd\u53ef\u4ee5\u6682\u65f6\u5ffd\u7565\u3002<\/p>\n<\/p>\n
3. \u7aef\u53e3\u53f7\u53ef\u80fd\u88ab\u5360\u7528，\u6216\u8005\u6743\u9650\u95ee\u9898（\u6bd4\u5982\u7ed1\u5b9a\u5230\u4f4e\u4e8e1024\u7684\u7aef\u53e3\u9700\u8981root\u6743\u9650），\u6240\u4ee5\u8fd9\u91cc\u9009\u4e00\u4e2a\u8f83\u9ad8\u7684\u7aef\u53e3，\u6bd4\u598212345\u3002<\/p>\n<\/p>\n
4. recv\u548csend\u7684\u8fd4\u56de\u503c\u5904\u7406：recv\u8fd4\u56de\u5b9e\u9645\u8bfb\u53d6\u7684\u5b57\u8282\u6570，\u53ef\u80fd\u6bd4\u8bf7\u6c42\u7684\u5c11，\u6240\u4ee5\u9700\u8981\u5faa\u73af\u8bfb\u53d6？\u4e0d\u8fc7\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d，\u53ef\u80fd\u4e0d\u9700\u8981，\u56e0\u4e3a\u5982\u679c\u6570\u636e\u91cf\u5927，\u53ef\u80fd\u9700\u8981\u591a\u6b21\u8bfb\u53d6，\u4f46\u56de\u663e\u670d\u52a1\u5668\u4e00\u822c\u53ef\u80fd\u4e0d\u9700\u8981，\u6bcf\u6b21\u8bfb\u53d6\u5c3d\u53ef\u80fd\u591a\u7684\u6570\u636e，\u7136\u540e\u53d1\u9001\u56de\u53bb\u5373\u53ef\u3002\u4f46\u8fd9\u91cc\u53ef\u80fd\u53ea\u662f\u7b80\u5355\u5904\u7406，\u6bcf\u6b21\u6700\u591a\u8bfb\u53d6255\u5b57\u8282，\u7136\u540e\u56de\u53d1\u3002\u5b9e\u9645\u5e94\u7528\u4e2d\u53ef\u80fd\u9700\u8981\u5904\u7406\u66f4\u5927\u7684\u6570\u636e\u548c\u66f4\u590d\u6742\u7684\u60c5\u51b5，\u4f46\u4f5c\u4e3a\u793a\u4f8b，\u53ef\u80fd\u8db3\u591f\u3002<\/p>\n<\/p>\n
\u53e6\u5916，\u5173\u4e8e\u7f51\u7edc\u5b57\u8282\u5e8f\u7684\u95ee\u9898，serv_addr\u7684\u7aef\u53e3\u53f7\u9700\u8981\u7528htons\u8f6c\u6362，\u5730\u5740\u7528INADDR_ANY\u5df2\u7ecf\u662f\u7f51\u7edc\u5b57\u8282\u5e8f\u5417？\u662f\u7684，\u56e0\u4e3aINADDR_ANY\u901a\u5e38\u662f0，\u6240\u4ee5\u65e0\u6240\u8c13，\u4f46\u5176\u4ed6\u60c5\u51b5\u4e0b\u9700\u8981inet_addr\u6216inet_pton\u6765\u5904\u7406IP\u5730\u5740\u7684\u8f6c\u6362\u3002<\/p>\n<\/p>\n
\u73b0\u5728，\u6d4b\u8bd5\u8fd9\u4e2a\u7a0b\u5e8f\u662f\u5426\u53ef\u884c\u3002\u7f16\u8bd1\u4e4b\u540e\u8fd0\u884c，\u7528telnet\u6216\u8005nc\u547d\u4ee4\u8fde\u63a5，\u53d1\u9001\u6570\u636e，\u770b\u662f\u5426\u56de\u663e\u3002<\/p>\n<\/p>\n
\u53ef\u80fd\u7684\u9519\u8bef\u70b9：<\/p>\n<\/p>\n
– \u5728fork\u4e4b\u540e，\u5b50\u8fdb\u7a0b\u548c\u7236\u8fdb\u7a0b\u90fd\u8981\u6b63\u786e\u5173\u95ed\u4e0d\u9700\u8981\u7684\u5957\u63a5\u5b57\u3002\u6bd4\u5982\u5b50\u8fdb\u7a0b\u5173\u95ed\u76d1\u542c\u5957\u63a5\u5b57，\u7236\u8fdb\u7a0b\u5173\u95ed\u8fde\u63a5\u5957\u63a5\u5b57，\u5426\u5219\u53ef\u80fd\u5bfc\u81f4\u8d44\u6e90\u6cc4\u6f0f\u3002<\/p>\n<\/p>\n
– \u5728\u5faa\u73af\u8bfb\u53d6\u6570\u636e\u65f6，\u5f53recv\u8fd4\u56de0\u65f6，\u8868\u793a\u5ba2\u6237\u7aef\u5173\u95ed\u4e86\u8fde\u63a5，\u8fd9\u65f6\u5019\u5e94\u8be5\u9000\u51fa\u5faa\u73af，\u5173\u95ed\u8fde\u63a5\u5957\u63a5\u5b57，\u5b50\u8fdb\u7a0b\u7ed3\u675f\u3002<\/p>\n<\/p>\n
\u8fd9\u6837\u5e94\u8be5\u53ef\u4ee5\u5904\u7406\u6bcf\u4e2a\u8fde\u63a5\u3002\u6bcf\u4e2a\u5ba2\u6237\u7aef\u8fde\u63a5\u540e，\u670d\u52a1\u5668\u4f1a\u521b\u5efa\u4e00\u4e2a\u5b50\u8fdb\u7a0b\u6765\u5904\u7406\u56de\u663e，\u4e3b\u8fdb\u7a0b\u7ee7\u7eed\u7b49\u5f85\u5176\u4ed6\u8fde\u63a5\u3002<\/p>\n<\/p>\n
\u6b64\u5916，\u9700\u8981\u786e\u4fdd\u7f16\u8bd1\u65f6\u94fe\u63a5\u76f8\u5e94\u7684\u5e93，\u6bd4\u5982\u5728Linux\u4e0b\u7528gcc\u7f16\u8bd1，\u4e0d\u9700\u8981\u7279\u522b\u7684\u5e93，\u4f46\u8981\u6ce8\u610f\u4ee3\u7801\u4e2d\u7684\u5934\u6587\u4ef6\u662f\u5426\u6b63\u786e\u3002<\/p>\n<\/p>\n
\u7efc\u4e0a，\u8fd9\u6837\u7684\u4ee3\u7801\u5e94\u8be5\u53ef\u4ee5\u5b9e\u73b0\u4e00\u4e2a\u57fa\u672c\u7684TCP\u56de\u663e\u670d\u52a1\u5668\u3002\u53ef\u80fd\u8fd8\u6709\u4e00\u4e9b\u7ec6\u8282\u9700\u8981\u8c03\u6574，\u6bd4\u5982\u5904\u7406recv\u548csend\u7684\u8fd4\u56de\u503c\u662f\u5426\u6b63\u786e，\u6bd4\u5982n\u53ef\u80fd\u5c0f\u4e8e\u9884\u671f\u7684\u5b57\u8282\u6570，\u662f\u5426\u9700\u8981\u5faa\u73af\u53d1\u9001？\u4f8b\u5982，send\u53ef\u80fd\u6ca1\u6709\u4e00\u6b21\u6027\u53d1\u9001\u6240\u6709\u6570\u636e，\u53ef\u80fd\u9700\u8981\u591a\u6b21\u53d1\u9001\u3002\u4f46\u662f\u5728\u56de\u663e\u7684\u60c5\u51b5\u4e0b，\u53ef\u80fd\u53ef\u4ee5\u5ffd\u7565，\u56e0\u4e3a\u5982\u679c\u7f51\u7edc\u6b63\u5e38\u7684\u8bdd，\u4e00\u822csend\u4f1a\u53d1\u9001\u5168\u90e8\u6570\u636e\u3002\u4f46\u4e3a\u4e86\u5065\u58ee\u6027，\u53ef\u80fd\u9700\u8981\u5faa\u73af\u53d1\u9001，\u76f4\u5230\u6240\u6709\u6570\u636e\u90fd\u53d1\u9001\u5b8c\u6bd5\u3002<\/p>\n<\/p>\n
\u4f8b\u5982，\u5728\u53d1\u9001\u90e8\u5206：<\/p>\n<\/p>\n
int bytes_sent = 0;<\/p>\n
while (bytes_sent < n) {<\/p>\n
int result = send(newsockfd, buffer + bytes_sent, n – bytes_sent, 0);<\/p>\n
if (result < 0) {<\/p>\n
perror("ERROR writing to socket");<\/p>\n
break;<\/p>\n
}<\/p>\n
bytes_sent += result;<\/p>\n
}<\/p>\n<\/p>\n
\u540c\u6837，recv\u53ef\u80fd\u4e5f\u9700\u8981\u591a\u6b21\u8bfb\u53d6，\u76f4\u5230\u6536\u5230\u6240\u6709\u9884\u671f\u7684\u6570\u636e？\u4e0d\u8fc7\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d，\u56e0\u4e3a\u5ba2\u6237\u7aef\u53d1\u9001\u7684\u6570\u636e\u53ef\u80fd\u4e0d\u5b9a\u957f，\u6240\u4ee5\u6bcf\u6b21\u8bfb\u53d6\u5c3d\u53ef\u80fd\u591a\u7684\u6570\u636e，\u7136\u540e\u7acb\u5373\u56de\u53d1\u3002\u6240\u4ee5\u53ef\u80fd\u4e0d\u9700\u8981\u5faa\u73af\u8bfb\u53d6，\u800c\u662f\u4e00\u6b21\u8bfb\u53d6，\u4e00\u6b21\u53d1\u9001\u3002\u4f46\u8fd9\u6837\u7684\u8bdd，\u5982\u679c\u5ba2\u6237\u7aef\u53d1\u9001\u7684\u6570\u636e\u91cf\u5f88\u5927，\u8d85\u8fc7\u7f13\u51b2\u533a，\u53ef\u80fd\u9700\u8981\u591a\u6b21\u8bfb\u53d6\u3002\u4e0d\u8fc7\u5bf9\u4e8e\u8fd9\u4e2a\u4f8b\u5b50\u6765\u8bf4，\u53ef\u80fd\u53ef\u4ee5\u63a5\u53d7\u3002<\/p>\n<\/p>\n
\u603b\u7ed3，\u4ee3\u7801\u7684\u5927\u81f4\u7ed3\u6784\u662f\u6b63\u786e\u7684，\u53ef\u80fd\u9700\u8981\u6ce8\u610f\u4e00\u4e9b\u7ec6\u8282，\u6bd4\u5982\u5904\u7406send\u548crecv\u7684\u8fd4\u56de\u503c，\u786e\u4fdd\u6240\u6709\u6570\u636e\u90fd\u88ab\u6b63\u786e\u53d1\u9001\u548c\u63a5\u6536\u3002\u6b64\u5916，\u5904\u7406\u5b50\u8fdb\u7a0b\u7684\u56de\u6536\u95ee\u9898，\u907f\u514d\u50f5\u5c38\u8fdb\u7a0b\u3002\u901a\u8fc7\u8bbe\u7f6e\u5ffd\u7565SIGCHLD\u4fe1\u53f7，\u53ef\u4ee5\u81ea\u52a8\u5904\u7406\u3002<\/p>\n<\/p>\n
\u73b0\u5728，\u628a\u8fd9\u4e9b\u601d\u8def\u8f6c\u5316\u4e3a\u6700\u7ec8\u7684\u4ee3\u7801\u3002<\/p>\n
c<\/p>\n
\u590d\u5236<\/p>\n
#include <stdio.h>
\n#include <stdlib.h>
\n#include <string.h>
\n#include <unistd.h>
\n#include <signal.h>
\n#include <sys\/types.h>
\n#include <sys\/socket.h>
\n#include <netinet\/in.h>
\n#include <arpa\/inet.h><\/p>\n
#define BUFFER_SIZE 1024
\n#define PORT 12345<\/p>\n
void handle_client(int sockfd) {
\n char buffer[BUFFER_SIZE];
\n ssize_t bytes_received;<\/p>\n
while ((bytes_received = recv(sockfd, buffer, BUFFER_SIZE, 0)) > 0) {
\n ssize_t bytes_sent = 0;
\n while (bytes_sent < bytes_received) {
\n ssize_t result = send(sockfd, buffer + bytes_sent, bytes_received – bytes_sent, 0);
\n if (result < 0) {
\n perror("send failed");
\n close(sockfd);
\n return;
\n }
\n bytes_sent += result;
\n }
\n }<\/p>\n
if (bytes_received < 0) {
\n perror("recv failed");
\n }
\n close(sockfd);
\n}<\/p>\n
int main() {
\n int server_fd, client_fd;
\n struct sockaddr_in server_addr, client_addr;
\n socklen_t client_len = sizeof(client_addr);<\/p>\n
\/\/ \u5ffd\u7565SIGCHLD\u4fe1\u53f7\u907f\u514d\u50f5\u5c38\u8fdb\u7a0b
\n signal(SIGCHLD, SIG_IGN);<\/p>\n
\/\/ \u521b\u5efaTCP\u5957\u63a5\u5b57
\n if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
\n perror("socket creation failed");
\n exit(EXIT_FAILURE);
\n }<\/p>\n
\/\/ \u914d\u7f6e\u670d\u52a1\u5668\u5730\u5740
\n memset(&server_addr, 0, sizeof(server_addr));
\n server_addr.sin_family = AF_INET;
\n server_addr.sin_addr.s_addr = INADDR_ANY;
\n server_addr.sin_port = htons(PORT);<\/p>\n
\/\/ \u7ed1\u5b9a\u5957\u63a5\u5b57
\n if (bind(server_fd, (struct sockaddr*)&server_addr, sizeof(server_addr)) < 0) {
\n perror("bind failed");
\n close(server_fd);
\n exit(EXIT_FAILURE);
\n }<\/p>\n
\/\/ \u5f00\u59cb\u76d1\u542c
\n if (listen(server_fd, 5) < 0) {
\n perror("listen failed");
\n close(server_fd);
\n exit(EXIT_FAILURE);
\n }<\/p>\n
printf("Server listening on port %d…\\\\n", PORT);<\/p>\n
while (1) {
\n \/\/ \u63a5\u53d7\u65b0\u8fde\u63a5
\n if ((client_fd = accept(server_fd, (struct sockaddr*)&client_addr, &client_len)) < 0) {
\n perror("accept failed");
\n continue;
\n }<\/p>\n
\/\/ \u663e\u793a\u5ba2\u6237\u7aef\u4fe1\u606f
\n printf("New connection from %s:%d\\\\n",
\n inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));<\/p>\n
\/\/ \u521b\u5efa\u5b50\u8fdb\u7a0b\u5904\u7406\u5ba2\u6237\u7aef
\n pid_t pid = fork();
\n if (pid < 0) {
\n perror("fork failed");
\n close(client_fd);
\n } else if (pid == 0) { \/\/ \u5b50\u8fdb\u7a0b
\n close(server_fd); \/\/ \u5173\u95ed\u4e0d\u9700\u8981\u7684\u76d1\u542c\u5957\u63a5\u5b57
\n handle_client(client_fd);
\n exit(EXIT_SUCCESS);
\n } else { \/\/ \u7236\u8fdb\u7a0b
\n close(client_fd); \/\/ \u5173\u95ed\u4e0d\u9700\u8981\u7684\u5ba2\u6237\u7aef\u5957\u63a5\u5b57
\n }
\n }<\/p>\n
close(server_fd);
\n return 0;
\n} <\/p>\n
\u521b\u5efa\u5957\u63a5\u5b57：\u4f7f\u7528socket()\u521b\u5efaTCP\u5957\u63a5\u5b57<\/p>\n<\/li>\n
\u7ed1\u5b9a\u5730\u5740：\u7ed1\u5b9a\u5230\u6240\u6709\u63a5\u53e3（INADDR_ANY）\u7684\u6307\u5b9a\u7aef\u53e3<\/p>\n<\/li>\n
\u76d1\u542c\u8fde\u63a5：\u4f7f\u7528listen()\u8fdb\u5165\u76d1\u542c\u72b6\u6001<\/p>\n<\/li>\n
\u63a5\u53d7\u8fde\u63a5：\u901a\u8fc7accept()\u5faa\u73af\u63a5\u53d7\u65b0\u8fde\u63a5<\/p>\n<\/li>\n
\u591a\u8fdb\u7a0b\u5904\u7406：<\/p>\n
\u7236\u8fdb\u7a0b\u63a5\u53d7\u8fde\u63a5\u540e\u521b\u5efa\u5b50\u8fdb\u7a0b<\/p>\n<\/li>\n
\u5b50\u8fdb\u7a0b\u5904\u7406\u5ba2\u6237\u7aef\u901a\u4fe1（handle_client\u51fd\u6570）<\/p>\n<\/li>\n
\u7236\u8fdb\u7a0b\u7ee7\u7eed\u76d1\u542c\u65b0\u8fde\u63a5<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
\u6570\u636e\u5904\u7406：<\/p>\n
\u4f7f\u7528recv()\u63a5\u6536\u6570\u636e<\/p>\n<\/li>\n
\u4f7f\u7528send()\u786e\u4fdd\u5b8c\u6574\u53d1\u9001\u6240\u6709\u63a5\u6536\u5230\u7684\u6570\u636e<\/p>\n<\/li>\n
\u5f53\u5ba2\u6237\u7aef\u65ad\u5f00\u8fde\u63a5\u65f6\u81ea\u52a8\u6e05\u7406\u8d44\u6e90<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
bash<\/p>\n
\u590d\u5236<\/p>\n
gcc echo_server.c -o echo_server
\n.\/echo_server <\/p>\n
\u4f7f\u7528telnet\u6216netcat\u8fde\u63a5\u670d\u52a1\u5668：<\/p>\n
bash<\/p>\n
\u590d\u5236<\/p>\n
nc 127.0.0.1 12345 <\/p>\n
\u8f93\u5165\u4efb\u610f\u5185\u5bb9，\u670d\u52a1\u5668\u4f1a\u5c06\u76f8\u540c\u5185\u5bb9\u56de\u663e\u3002<\/p>\n
\u652f\u6301\u591a\u5ba2\u6237\u7aef\u5e76\u53d1\u8fde\u63a5<\/p>\n<\/li>\n
\u81ea\u52a8\u56de\u6536\u5b50\u8fdb\u7a0b\u8d44\u6e90<\/p>\n<\/li>\n
\u5b8c\u6574\u5904\u7406TCP\u6570\u636e\u6d41（\u5904\u7406\u77ed\u5305\u548c\u7c98\u5305\u95ee\u9898）<\/p>\n<\/li>\n
\u8be6\u7ec6\u7684\u9519\u8bef\u5904\u7406<\/p>\n<\/li>\n
\u663e\u793a\u5ba2\u6237\u7aef\u8fde\u63a5\u4fe1\u606f<\/p>\n<\/li>\n<\/ul>\n
\u8fd9\u4e2a\u5b9e\u73b0\u4f7f\u7528\u4e86\u4f20\u7edf\u7684\u591a\u8fdb\u7a0b\u6a21\u578b，\u9002\u5408\u6f14\u793a\u57fa\u672c\u7684TCP\u670d\u52a1\u5668\u5de5\u4f5c\u539f\u7406\u3002\u5728\u5b9e\u9645\u751f\u4ea7\u73af\u5883\u4e2d，\u53ef\u80fd\u4f1a\u4f7f\u7528\u66f4\u9ad8\u6548\u7684I\/O\u590d\u7528\u65b9\u5f0f（\u5982epoll）\u6216\u7ebf\u7a0b\u6c60\u6765\u5904\u7406\u5e76\u53d1\u8fde\u63a5\u3002<\/p>\n
\u5df2\u6df1\u5ea6\u601d\u8003（\u7528\u65f6 27 \u79d2）<\/p>\n
\u597d\u7684，\u7528\u6237\u95ee\u7684\u662f\u4e3a\u4ec0\u4e48\u4f7f\u7528signal(SIGCHLD, SIG_IGN);\u53ef\u4ee5\u907f\u514d\u50f5\u5c38\u8fdb\u7a0b\u3002\u6211\u9700\u8981\u5148\u56de\u987e\u4e00\u4e0b\u50f5\u5c38\u8fdb\u7a0b\u7684\u76f8\u5173\u77e5\u8bc6\u3002<\/p>\n<\/p>\n
\u9996\u5148，\u50f5\u5c38\u8fdb\u7a0b\u662f\u4ec0\u4e48？\u5f53\u5b50\u8fdb\u7a0b\u7ed3\u675f\u8fd0\u884c\u65f6，\u7236\u8fdb\u7a0b\u9700\u8981\u8c03\u7528wait\u6216waitpid\u6765\u83b7\u53d6\u5b50\u8fdb\u7a0b\u7684\u9000\u51fa\u72b6\u6001，\u5426\u5219\u5b50\u8fdb\u7a0b\u7684\u8fdb\u7a0b\u63cf\u8ff0\u7b26\u4ecd\u7136\u4fdd\u7559\u5728\u7cfb\u7edf\u4e2d，\u53d8\u6210\u50f5\u5c38\u8fdb\u7a0b\u3002\u8fd9\u4f1a\u5bfc\u81f4\u8d44\u6e90\u6d6a\u8d39，\u5982\u679c\u5927\u91cf\u50f5\u5c38\u8fdb\u7a0b\u5b58\u5728，\u53ef\u80fd\u4f1a\u5f71\u54cd\u7cfb\u7edf\u6027\u80fd\u3002<\/p>\n<\/p>\n
\u90a3\u7528\u6237\u63d0\u4f9b\u7684\u4ee3\u7801\u4e2d，\u7236\u8fdb\u7a0b\u5728\u5904\u7406\u5b8c\u5ba2\u6237\u7aef\u8fde\u63a5\u540e，\u901a\u8fc7fork\u521b\u5efa\u5b50\u8fdb\u7a0b\u3002\u5b50\u8fdb\u7a0b\u5904\u7406\u5b8c\u5ba2\u6237\u7aef\u8bf7\u6c42\u540e\u9000\u51fa，\u8fd9\u65f6\u5019\u7236\u8fdb\u7a0b\u5982\u679c\u6ca1\u6709\u5904\u7406\u5b50\u8fdb\u7a0b\u7684\u7ec8\u6b62\u72b6\u6001，\u5c31\u4f1a\u4ea7\u751f\u50f5\u5c38\u8fdb\u7a0b\u3002<\/p>\n<\/p>\n
\u901a\u5e38\u5904\u7406SIGCHLD\u4fe1\u53f7\u7684\u65b9\u6cd5\u662f\u5728\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u4e2d\u8c03\u7528wait\u6216waitpid\u6765\u56de\u6536\u5b50\u8fdb\u7a0b\u3002\u4f46\u7528\u6237\u4ee3\u7801\u4e2d\u4f7f\u7528\u7684\u662fsignal(SIGCHLD, SIG_IGN);，\u4e5f\u5c31\u662f\u5ffd\u7565SIGCHLD\u4fe1\u53f7\u3002\u8fd9\u91cc\u9700\u8981\u7406\u89e3\u4e3a\u4ec0\u4e48\u5ffd\u7565\u8fd9\u4e2a\u4fe1\u53f7\u53ef\u4ee5\u907f\u514d\u50f5\u5c38\u8fdb\u7a0b\u3002<\/p>\n<\/p>\n
\u6839\u636e\u4e4b\u524d\u5b66\u7684\u77e5\u8bc6，\u5f53\u7236\u8fdb\u7a0b\u5ffd\u7565SIGCHLD\u4fe1\u53f7\u65f6，\u7cfb\u7edf\u4f1a\u81ea\u52a8\u56de\u6536\u5b50\u8fdb\u7a0b\u7684\u9000\u51fa\u72b6\u6001，\u4e0d\u4f1a\u8ba9\u5b50\u8fdb\u7a0b\u53d8\u6210\u50f5\u5c38\u8fdb\u7a0b\u3002\u8fd9\u662f\u56e0\u4e3a\u5f53\u4fe1\u53f7\u88ab\u8bbe\u7f6e\u4e3aSIG_IGN\u65f6，\u5185\u6838\u4f1a\u5904\u7406\u7ec8\u6b62\u7684\u5b50\u8fdb\u7a0b，\u76f4\u63a5\u91ca\u653e\u76f8\u5173\u8d44\u6e90，\u4e0d\u9700\u8981\u7236\u8fdb\u7a0b\u4e3b\u52a8\u8c03\u7528wait\u3002\u8fd9\u53ef\u80fd\u662fPOSIX\u6807\u51c6\u4e2d\u7684\u884c\u4e3a，\u4f46\u9700\u8981\u786e\u8ba4\u4e0d\u540cUNIX\u7cfb\u7edf\u7684\u517c\u5bb9\u6027\u3002<\/p>\n<\/p>\n
\u4e0d\u8fc7，\u9700\u8981\u6ce8\u610f\u7684\u662f，\u4e0d\u662f\u6240\u6709\u7cfb\u7edf\u90fd\u652f\u6301\u8fd9\u79cd\u884c\u4e3a\u3002\u6bd4\u5982，\u5728System V\u7684\u4f20\u7edf\u4e2d，\u5ffd\u7565SIGCHLD\u5e76\u4e0d\u80fd\u963b\u6b62\u50f5\u5c38\u8fdb\u7a0b\u7684\u4ea7\u751f，\u5fc5\u987b\u663e\u5f0f\u5904\u7406\u3002\u4f46\u6839\u636e\u7528\u6237\u63d0\u4f9b\u7684\u4ee3\u7801\u662f\u5728Linux\u73af\u5883\u4e0b\u8fd0\u884c\u7684，\u800cLinux\u9075\u5faa\u7684\u662fBSD\u7684\u884c\u4e3a，\u5f53\u5ffd\u7565SIGCHLD\u65f6，\u5b50\u8fdb\u7a0b\u7ec8\u6b62\u540e\u4f1a\u88ab\u81ea\u52a8\u56de\u6536，\u4e0d\u4f1a\u53d8\u6210\u50f5\u5c38\u8fdb\u7a0b\u3002\u56e0\u6b64，\u8fd9\u6837\u7684\u8bbe\u7f6e\u786e\u5b9e\u6709\u6548\u3002<\/p>\n<\/p>\n
\u8fd9\u6837\u5904\u7406\u7684\u597d\u5904\u662f\u4ee3\u7801\u66f4\u7b80\u6d01，\u4e0d\u9700\u8981\u5728\u7236\u8fdb\u7a0b\u4e2d\u8bbe\u7f6e\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u6216\u8005\u8c03\u7528wait\u3002\u5bf9\u4e8e\u7b80\u5355\u7684\u670d\u52a1\u5668\u7a0b\u5e8f\u6765\u8bf4，\u8fd9\u53ef\u80fd\u662f\u4e00\u4e2a\u65b9\u4fbf\u7684\u89e3\u51b3\u65b9\u6848\u3002\u4f46\u9700\u8981\u6307\u51fa，\u8fd9\u79cd\u505a\u6cd5\u53ef\u80fd\u5728\u67d0\u4e9bUNIX\u53d8\u79cd\u4e2d\u4e0d\u53ef\u884c，\u4f46\u5728Linux\u4e0b\u662f\u6709\u6548\u7684\u3002<\/p>\n<\/p>\n
\u603b\u7ed3\u4e00\u4e0b，\u7528\u6237\u7684\u95ee\u9898\u6838\u5fc3\u5728\u4e8e\u7406\u89e3\u5ffd\u7565SIGCHLD\u4fe1\u53f7\u5982\u4f55\u907f\u514d\u50f5\u5c38\u8fdb\u7a0b\u3002\u9700\u8981\u89e3\u91caSIGCHLD\u7684\u4f5c\u7528，\u50f5\u5c38\u8fdb\u7a0b\u7684\u6210\u56e0，\u4ee5\u53ca\u5ffd\u7565\u8be5\u4fe1\u53f7\u540e\u7cfb\u7edf\u5982\u4f55\u5904\u7406\u5b50\u8fdb\u7a0b\u7684\u9000\u51fa\u72b6\u6001\u3002\u6b64\u5916，\u8fd8\u8981\u63d0\u5230\u4e0d\u540c\u7cfb\u7edf\u7684\u5dee\u5f02，\u786e\u4fdd\u7528\u6237\u77e5\u9053\u8fd9\u79cd\u65b9\u6cd5\u7684\u9002\u7528\u73af\u5883\u3002<\/p>\n<\/p>\n
\u5728\u56de\u7b54\u65f6，\u5e94\u8be5\u5206\u6b65\u9aa4\u89e3\u91ca，\u9996\u5148\u8bf4\u660e\u50f5\u5c38\u8fdb\u7a0b\u7684\u4ea7\u751f\u539f\u56e0，\u7136\u540e\u8bf4\u660eSIGCHLD\u4fe1\u53f7\u7684\u4f5c\u7528，\u63a5\u7740\u89e3\u91ca\u5ffd\u7565\u8be5\u4fe1\u53f7\u65f6\u7cfb\u7edf\u7684\u884c\u4e3a，\u6700\u540e\u63d0\u53ca\u517c\u5bb9\u6027\u548c\u6ce8\u610f\u4e8b\u9879\u3002\u8fd9\u6837\u7528\u6237\u80fd\u6e05\u6670\u5730\u7406\u89e3\u6574\u4e2a\u8fc7\u7a0b，\u5e76\u77e5\u9053\u5728\u4f55\u79cd\u60c5\u51b5\u4e0b\u4f7f\u7528\u8fd9\u79cd\u65b9\u6cd5\u5408\u9002\u3002<\/p>\n
\u5728Linux\u7cfb\u7edf\u4e2d，signal(SIGCHLD, SIG_IGN);\u00a0\u8fd9\u4e00\u884c\u4ee3\u7801\u80fd\u907f\u514d\u50f5\u5c38\u8fdb\u7a0b\u7684\u539f\u56e0\u4e0eUNIX\u7cfb\u7edf\u7684\u8fdb\u7a0b\u7ba1\u7406\u673a\u5236\u5bc6\u5207\u76f8\u5173\u3002\u4ee5\u4e0b\u662f\u5206\u6b65\u89e3\u91ca：<\/p>\n
\u4ec0\u4e48\u662f\u50f5\u5c38\u8fdb\u7a0b \u5f53\u5b50\u8fdb\u7a0b\u7ec8\u6b62\u65f6，\u5b83\u4e0d\u4f1a\u7acb\u5373\u4ece\u7cfb\u7edf\u4e2d\u6d88\u5931\u3002 \u7236\u8fdb\u7a0b\u5fc5\u987b\u8c03\u7528\u00a0wait()\u00a0\u6216\u00a0waitpid()\u00a0\u6765\u8bfb\u53d6\u5b50\u8fdb\u7a0b\u7684\u9000\u51fa\u72b6\u6001\u3002 \u5982\u679c\u7236\u8fdb\u7a0b\u6ca1\u6709\u505a\u8fd9\u4ef6\u4e8b，\u5b50\u8fdb\u7a0b\u7684\u8fdb\u7a0b\u63cf\u8ff0\u7b26（PID）\u4f1a\u6b8b\u7559\u5728\u7cfb\u7edf\u4e2d，\u6210\u4e3a\u50f5\u5c38\u8fdb\u7a0b（Zombie Process）\u3002<\/p>\n<\/li>\n
\u50f5\u5c38\u8fdb\u7a0b\u7684\u5371\u5bb3 \u5360\u7528\u7cfb\u7edf\u8d44\u6e90（PID\u6709\u9650），\u5927\u91cf\u50f5\u5c38\u8fdb\u7a0b\u53ef\u80fd\u5bfc\u81f4\u65e0\u6cd5\u521b\u5efa\u65b0\u8fdb\u7a0b\u3002<\/p>\n<\/li>\n
\u4fe1\u53f7\u89e6\u53d1\u6761\u4ef6 \u5f53\u5b50\u8fdb\u7a0b\u7ec8\u6b62\u65f6，\u5185\u6838\u4f1a\u5411\u7236\u8fdb\u7a0b\u53d1\u9001\u00a0SIGCHLD\u00a0\u4fe1\u53f7，\u901a\u77e5\u7236\u8fdb\u7a0b"\u6709\u5b50\u8fdb\u7a0b\u9000\u51fa\u4e86"\u3002<\/p>\n<\/li>\n
\u9ed8\u8ba4\u884c\u4e3a \u9ed8\u8ba4\u60c5\u51b5\u4e0b，SIGCHLD\u00a0\u4fe1\u53f7\u7684\u9ed8\u8ba4\u5904\u7406\u65b9\u5f0f\u662f\u5ffd\u7565（SIG_DFL），\u4f46\u4e0d\u4f1a\u81ea\u52a8\u56de\u6536\u50f5\u5c38\u8fdb\u7a0b\u3002 \u6b64\u65f6\u5982\u679c\u7236\u8fdb\u7a0b\u4e0d\u4e3b\u52a8\u8c03\u7528\u00a0wait()，\u50f5\u5c38\u8fdb\u7a0b\u4ecd\u7136\u4f1a\u5b58\u5728\u3002<\/p>\n<\/li>\n
\u663e\u5f0f\u5ffd\u7565\u4fe1\u53f7 \u901a\u8fc7\u00a0signal(SIGCHLD, SIG_IGN);\u00a0\u663e\u5f0f\u544a\u77e5\u7cfb\u7edf："\u7236\u8fdb\u7a0b\u5b8c\u5168\u4e0d\u60f3\u5173\u5fc3\u5b50\u8fdb\u7a0b\u7684\u9000\u51fa\u72b6\u6001"\u3002<\/p>\n<\/li>\n
\u5185\u6838\u7684\u4f18\u5316\u5904\u7406 \u5728Linux（\u4ee5\u53ca\u5927\u591a\u6570\u73b0\u4ee3UNIX\u7cfb\u7edf）\u4e2d，\u5f53\u8bbe\u7f6e\u4e86\u00a0SIGCHLD\u00a0\u7684\u5904\u7406\u65b9\u5f0f\u4e3a\u00a0SIG_IGN\u00a0\u65f6：<\/p>\n
\u5185\u6838\u4f1a\u7acb\u5373\u81ea\u52a8\u56de\u6536\u6240\u6709\u7ec8\u6b62\u7684\u5b50\u8fdb\u7a0b<\/p>\n<\/li>\n
\u4e0d\u518d\u4fdd\u7559\u5b50\u8fdb\u7a0b\u7684\u9000\u51fa\u72b6\u6001\u4fe1\u606f<\/p>\n<\/li>\n
\u5b50\u8fdb\u7a0b\u4e0d\u4f1a\u8fdb\u5165\u50f5\u5c38\u72b6\u6001<\/p>\n<\/li>\n
\u7236\u8fdb\u7a0b\u4e0d\u9700\u8981（\u4e5f\u65e0\u6cd5）\u8c03\u7528\u00a0wait()\u00a0\u51fd\u6570<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
\u5386\u53f2\u5dee\u5f02<\/p>\n
\u5728System V UNIX\u7cfb\u7edf\u4e2d，\u5373\u4f7f\u8bbe\u7f6e\u4e86\u00a0SIG_IGN，\u4ecd\u7136\u4f1a\u4ea7\u751f\u50f5\u5c38\u8fdb\u7a0b<\/p>\n<\/li>\n
\u4f46\u5728BSD\u6d3e\u751f\u7684\u7cfb\u7edf（\u5305\u62ecLinux）\u4e2d，SIG_IGN\u00a0\u4f1a\u89e6\u53d1\u81ea\u52a8\u56de\u6536\u884c\u4e3a<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
POSIX\u6807\u51c6 POSIX.1-2001\u660e\u786e\u89c4\u5b9a\u4e86\u8fd9\u79cd\u884c\u4e3a\u7684\u5408\u6cd5\u6027，\u56e0\u6b64\u73b0\u4ee3\u7cfb\u7edf\u90fd\u4f1a\u9075\u5b88\u6b64\u89c4\u8303\u3002<\/p>\n<\/li>\n
c<\/p>\n
\u590d\u5236<\/p>\n
#include <stdio.h>
\n#include <stdlib.h>
\n#include <unistd.h>
\n#include <signal.h><\/p>\n
int main() {
\n signal(SIGCHLD, SIG_IGN); \/\/ \u5173\u952e\u4ee3\u7801<\/p>\n
pid_t pid = fork();
\n if (pid == 0) {
\n \/\/ \u5b50\u8fdb\u7a0b\u7acb\u5373\u9000\u51fa
\n printf("Child process %d exiting\\\\n", getpid());
\n exit(0);
\n } else {
\n \/\/ \u7236\u8fdb\u7a0b\u4e0d\u8c03\u7528wait()
\n printf("Parent process %d sleeping\\\\n", getpid());
\n sleep(30);
\n }
\n return 0;
\n} <\/p>\n
\u8fd0\u884c\u89c2\u5bdf： \u4f7f\u7528\u00a0ps aux | grep Z\u00a0\u547d\u4ee4\u89c2\u5bdf\u8fdb\u7a0b\u72b6\u6001，\u4e0d\u4f1a\u51fa\u73b0\u50f5\u5c38\u8fdb\u7a0b\u3002<\/p>\n
\u4fe1\u606f\u4e22\u5931 \u4f7f\u7528\u00a0SIG_IGN\u00a0\u540e，\u7236\u8fdb\u7a0b\u5c06\u5b8c\u5168\u65e0\u6cd5\u83b7\u53d6\u5b50\u8fdb\u7a0b\u7684\u9000\u51fa\u72b6\u6001（\u8fd4\u56de\u7801\u7b49）\u3002<\/p>\n<\/li>\n
\u53ef\u79fb\u690d\u6027 \u867d\u7136\u73b0\u4ee3\u7cfb\u7edf\u666e\u904d\u652f\u6301\u8be5\u7279\u6027，\u4f46\u5728\u4e00\u4e9b\u65e7\u7248UNIX\u7cfb\u7edf\u4e0a\u53ef\u80fd\u4e0d\u9002\u7528\u3002 \u66f4\u6807\u51c6\u7684\u5199\u6cd5\u662f\u663e\u5f0f\u8bbe\u7f6e\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u5e76\u5728\u5176\u4e2d\u8c03\u7528\u00a0waitpid：<\/p>\n
c<\/p>\n
\u590d\u5236<\/p>\n
void sigchld_handler(int sig) {
\n while(waitpid(-1, NULL, WNOHANG) > 0);
\n}
\nsignal(SIGCHLD, sigchld_handler); <\/li>\n
\u4e0e\u00a0waitpid()\u00a0\u7684\u533a\u522b SIG_IGN\u00a0\u65b9\u5f0f\u9002\u5408"\u4e0d\u5173\u5fc3\u5b50\u8fdb\u7a0b\u7ed3\u679c"\u7684\u573a\u666f，\u800c\u9700\u8981\u6536\u96c6\u5b50\u8fdb\u7a0b\u4fe1\u606f\u65f6\u4ecd\u9700\u4f7f\u7528\u4f20\u7edf\u65b9\u5f0f\u3002<\/p>\n<\/li>\n
signal(SIGCHLD, SIG_IGN);\u00a0\u901a\u8fc7\u544a\u8bc9\u5185\u6838"\u7236\u8fdb\u7a0b\u5b8c\u5168\u4e0d\u9700\u8981\u5b50\u8fdb\u7a0b\u7684\u9000\u51fa\u4fe1\u606f"，\u4f7f\u5f97\u5185\u6838\u81ea\u52a8\u56de\u6536\u7ec8\u6b62\u7684\u5b50\u8fdb\u7a0b\u8d44\u6e90，\u4ece\u800c\u4ece\u6839\u672c\u4e0a\u907f\u514d\u4e86\u50f5\u5c38\u8fdb\u7a0b\u7684\u4ea7\u751f\u3002\u8fd9\u79cd\u65b9\u5f0f：<\/p>\n
\u7b80\u6d01\u9ad8\u6548（\u65e0\u9700\u5faa\u73af\u8c03\u7528\u00a0wait()）<\/p>\n<\/li>\n
\u9002\u5408\u4e0d\u9700\u8981\u6536\u96c6\u5b50\u8fdb\u7a0b\u72b6\u6001\u7684\u573a\u666f<\/p>\n<\/li>\n
\u662f\u73b0\u4ee3Linux\u7cfb\u7edf\u4e2d\u5904\u7406\u50f5\u5c38\u8fdb\u7a0b\u7684\u63a8\u8350\u65b9\u5f0f\u4e4b\u4e00<\/p>\n<\/li>\n<\/ul>\n
\u5df2\u6df1\u5ea6\u601d\u8003（\u7528\u65f6 26 \u79d2）<\/p>\n
\u597d\u7684，\u7528\u6237\u95ee\u7684\u662f\u5173\u4e8eclose(server_fd)\u548cclose(client_fd)\u8fd9\u4e24\u884c\u4ee3\u7801\u7684\u610f\u601d\u3002\u6211\u9700\u8981\u5148\u7406\u89e3\u7528\u6237\u7684\u95ee\u9898\u80cc\u666f\u3002\u7528\u6237\u4e4b\u524d\u95ee\u8fc7\u5173\u4e8eTCP\u670d\u52a1\u5668\u7684\u4ee3\u7801，\u73b0\u5728\u9488\u5bf9\u4ee3\u7801\u4e2d\u7684\u5177\u4f53\u4e24\u884c\u5173\u95ed\u5957\u63a5\u5b57\u7684\u64cd\u4f5c\u6709\u7591\u95ee\u3002\u7528\u6237\u53ef\u80fd\u662f\u5728\u5b66\u4e60\u7f51\u7edc\u7f16\u7a0b，\u6216\u8005\u6b63\u5728\u7f16\u5199\u7c7b\u4f3c\u7684\u670d\u52a1\u5668\u7a0b\u5e8f，\u5bf9\u8d44\u6e90\u7ba1\u7406\u4e0d\u592a\u6e05\u695a\u3002<\/p>\n<\/p>\n
\u9996\u5148，\u6211\u8981\u56de\u987e\u4e4b\u524d\u7684\u5bf9\u8bdd\u3002\u7528\u6237\u4e4b\u524d\u5f97\u5230\u4e86\u4e00\u4e2a\u7528C\u5199\u7684TCP\u56de\u663e\u670d\u52a1\u5668\u4ee3\u7801，\u91cc\u9762\u5728\u7236\u8fdb\u7a0b\u548c\u5b50\u8fdb\u7a0b\u4e2d\u5206\u522b\u5173\u95ed\u4e86server_fd\u548cclient_fd\u3002\u7528\u6237\u73b0\u5728\u60f3\u77e5\u9053\u8fd9\u4e24\u884c\u4ee3\u7801\u7684\u5177\u4f53\u4f5c\u7528，\u4e3a\u4ec0\u4e48\u9700\u8981\u5206\u522b\u5173\u95ed\u8fd9\u4e24\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u3002<\/p>\n<\/p>\n
\u63a5\u4e0b\u6765，\u6211\u9700\u8981\u5206\u6790\u8fd9\u4e24\u884c\u4ee3\u7801\u7684\u4e0a\u4e0b\u6587\u3002\u5728\u7236\u8fdb\u7a0b\u4e2d，\u5f53accept\u5230\u65b0\u7684\u5ba2\u6237\u7aef\u8fde\u63a5\u540e，fork\u51fa\u4e00\u4e2a\u5b50\u8fdb\u7a0b\u6765\u5904\u7406\u8fd9\u4e2a\u5ba2\u6237\u7aef\u3002\u7236\u8fdb\u7a0b\u5728fork\u4e4b\u540e，\u7acb\u5373\u5173\u95edclient_fd，\u800c\u5b50\u8fdb\u7a0b\u5219\u5173\u95edserver_fd，\u7136\u540e\u5904\u7406client_fd\u3002<\/p>\n<\/p>\n
\u7528\u6237\u53ef\u80fd\u4e0d\u592a\u7406\u89e3\u4e3a\u4ec0\u4e48\u7236\u5b50\u8fdb\u7a0b\u9700\u8981\u5206\u522b\u5173\u95ed\u4e0d\u540c\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26，\u5c24\u5176\u662f\u6587\u4ef6\u63cf\u8ff0\u7b26\u5728fork\u4e4b\u540e\u7684\u884c\u4e3a\u3002\u8fd9\u91cc\u6d89\u53ca\u5230\u8fdb\u7a0b\u95f4\u6587\u4ef6\u63cf\u8ff0\u7b26\u7684\u7ee7\u627f\u4ee5\u53ca\u5f15\u7528\u8ba1\u6570\u7684\u6982\u5ff5\u3002<\/p>\n<\/p>\n
\u6211\u9700\u8981\u89e3\u91ca\u6e05\u695a，\u6bcf\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26\u90fd\u662f\u4e00\u4e2a\u7cfb\u7edf\u8d44\u6e90，\u5f53fork\u65f6，\u5b50\u8fdb\u7a0b\u4f1a\u590d\u5236\u7236\u8fdb\u7a0b\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\u8868，\u6240\u4ee5\u7236\u8fdb\u7a0b\u548c\u5b50\u8fdb\u7a0b\u5404\u81ea\u6301\u6709\u8fd9\u4e9b\u6587\u4ef6\u63cf\u8ff0\u7b26\u7684\u526f\u672c\u3002\u6bcf\u4e2a\u5957\u63a5\u5b57\u90fd\u6709\u4e00\u4e2a\u5f15\u7528\u8ba1\u6570，\u5f53\u6240\u6709\u6301\u6709\u5b83\u7684\u8fdb\u7a0b\u90fd\u5173\u95ed\u4e86，\u5957\u63a5\u5b57\u624d\u4f1a\u771f\u6b63\u88ab\u91ca\u653e\u3002<\/p>\n<\/p>\n
\u5bf9\u4e8e\u7236\u8fdb\u7a0b\u6765\u8bf4，\u5b83\u53ea\u9700\u8981\u7ee7\u7eed\u76d1\u542c\u65b0\u7684\u8fde\u63a5，\u6240\u4ee5\u4e0d\u9700\u8981\u4fdd\u6301\u5ba2\u6237\u7aef\u7684client_fd，\u5173\u95ed\u5b83\u53ef\u4ee5\u91ca\u653e\u8d44\u6e90，\u907f\u514d\u8d44\u6e90\u6cc4\u6f0f\u3002\u540c\u6837，\u5b50\u8fdb\u7a0b\u5904\u7406\u5ba2\u6237\u7aef\u8bf7\u6c42\u65f6\u4e0d\u9700\u8981\u76d1\u542c\u5957\u63a5\u5b57server_fd，\u5173\u95ed\u5b83\u53ef\u4ee5\u51cf\u5c11\u4e0d\u5fc5\u8981\u7684\u8d44\u6e90\u5360\u7528，\u540c\u65f6\u9632\u6b62\u5b50\u8fdb\u7a0b\u610f\u5916\u64cd\u4f5c\u76d1\u542c\u5957\u63a5\u5b57\u3002<\/p>\n<\/p>\n
\u7528\u6237\u53ef\u80fd\u5b58\u5728\u7684\u7591\u95ee\u70b9\u5305\u62ec：\u4e3a\u4ec0\u4e48\u8981\u5173\u95ed？\u4e0d\u5173\u95ed\u4f1a\u600e\u6837？\u7236\u5b50\u8fdb\u7a0b\u4e4b\u95f4\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\u662f\u5982\u4f55\u7ba1\u7406\u7684？\u8fd9\u65f6\u5019\u9700\u8981\u8be6\u7ec6\u89e3\u91ca\u5f15\u7528\u8ba1\u6570\u7684\u673a\u5236，\u4ee5\u53ca\u5982\u679c\u4e0d\u5173\u95ed\u7684\u8bdd\u53ef\u80fd\u5bfc\u81f4\u7684\u95ee\u9898，\u6bd4\u5982\u8d44\u6e90\u8017\u5c3d，\u65e0\u6cd5\u63a5\u53d7\u65b0\u8fde\u63a5，\u6216\u8005\u5ba2\u6237\u7aef\u8fde\u63a5\u65e0\u6cd5\u6b63\u786e\u5173\u95ed\u3002<\/p>\n<\/p>\n
\u53e6\u5916，\u7528\u6237\u53ef\u80fd\u5bf9\u591a\u8fdb\u7a0b\u7f16\u7a0b\u4e2d\u7684\u8d44\u6e90\u7ba1\u7406\u4e0d\u592a\u719f\u6089，\u9700\u8981\u5f3a\u8c03\u5728fork\u4e4b\u540e，\u7236\u5b50\u8fdb\u7a0b\u5e94\u8be5\u5404\u81ea\u5173\u95ed\u4e0d\u9700\u8981\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26，\u8fd9\u662f\u4e00\u79cd\u826f\u597d\u7684\u7f16\u7a0b\u4e60\u60ef，\u786e\u4fdd\u8d44\u6e90\u53ca\u65f6\u91ca\u653e，\u907f\u514d\u6f5c\u5728\u7684\u95ee\u9898\u3002<\/p>\n<\/p>\n
\u603b\u7ed3\u6765\u8bf4，\u7528\u6237\u9700\u8981\u7406\u89e3\u8fd9\u4e24\u4e2aclose\u64cd\u4f5c\u7684\u5fc5\u8981\u6027，\u4ee5\u53ca\u5b83\u4eec\u5982\u4f55\u5e2e\u52a9\u6b63\u786e\u7ba1\u7406\u670d\u52a1\u5668\u8d44\u6e90，\u9632\u6b62\u6587\u4ef6\u63cf\u8ff0\u7b26\u6cc4\u6f0f，\u786e\u4fdd\u670d\u52a1\u5668\u7684\u7a33\u5b9a\u8fd0\u884c\u3002<\/p>\n
\u5728TCP\u670d\u52a1\u5668\u7684\u591a\u8fdb\u7a0b\u5b9e\u73b0\u4e2d，close(server_fd)\u00a0\u548c\u00a0close(client_fd)\u00a0\u8fd9\u4e24\u884c\u4ee3\u7801\u6d89\u53caUNIX\u6587\u4ef6\u63cf\u8ff0\u7b26\u7ba1\u7406\u548c\u591a\u8fdb\u7a0b\u7f16\u7a0b\u7684\u6838\u5fc3\u673a\u5236\u3002\u4ee5\u4e0b\u662f\u6df1\u5165\u5206\u6790：<\/p>\n
\u5185\u6838\u8d44\u6e90<\/p>\n
\u6bcf\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26（\u5982\u00a0server_fd\u00a0\u548c\u00a0client_fd）\u672c\u8d28\u4e0a\u662f\u5185\u6838\u4e2d\u4e00\u4e2a\u6253\u5f00\u8d44\u6e90\u7684\u5f15\u7528\u53e5\u67c4<\/p>\n<\/li>\n
\u5957\u63a5\u5b57\u5728\u5185\u6838\u4e2d\u7531\u5f15\u7528\u8ba1\u6570\u7ba1\u7406，\u5f53\u5f15\u7528\u8ba1\u6570\u5f52\u96f6\u65f6\u624d\u4f1a\u771f\u6b63\u5173\u95ed<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
fork\u7684\u7279\u6027<\/p>\n
\u8c03\u7528\u00a0fork()\u00a0\u521b\u5efa\u5b50\u8fdb\u7a0b\u65f6，\u5b50\u8fdb\u7a0b\u4f1a\u590d\u5236\u7236\u8fdb\u7a0b\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\u8868<\/p>\n<\/li>\n
\u7236\u5b50\u8fdb\u7a0b\u4e2d\u7684\u76f8\u540c\u6587\u4ef6\u63cf\u8ff0\u7b26\u6307\u5411\u540c\u4e00\u4e2a\u5185\u6838\u5957\u63a5\u5b57\u5bf9\u8c61<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
c<\/p>\n
\u590d\u5236<\/p>\n
pid_t pid = fork();
\nif (pid == 0) { \/\/ \u5b50\u8fdb\u7a0b
\n close(server_fd); \/\/ \u5173\u95ed\u76d1\u542c\u5957\u63a5\u5b57
\n handle_client(client_fd);
\n exit(EXIT_SUCCESS);
\n} else { \/\/ \u7236\u8fdb\u7a0b
\n close(client_fd); \/\/ \u5173\u95ed\u5ba2\u6237\u7aef\u5957\u63a5\u5b57
\n} <\/p>\n
\u8d44\u6e90\u91ca\u653e\u5fc5\u8981\u6027<\/p>\n
\u5b50\u8fdb\u7a0b\u4ec5\u9700\u5904\u7406\u5df2\u63a5\u53d7\u7684\u5ba2\u6237\u7aef\u8fde\u63a5（client_fd）<\/p>\n<\/li>\n
\u76d1\u542c\u5957\u63a5\u5b57（server_fd）\u5bf9\u5b50\u8fdb\u7a0b\u65e0\u7528<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
\u907f\u514d\u8d44\u6e90\u6cc4\u6f0f<\/p>\n
\u5982\u679c\u4e0d\u5173\u95ed：<\/p>\n
\u5b50\u8fdb\u7a0b\u6301\u6709\u00a0server_fd\u00a0\u7684\u526f\u672c<\/p>\n<\/li>\n
\u5373\u4f7f\u7236\u8fdb\u7a0b\u7ed3\u675f，\u53ea\u8981\u5b50\u8fdb\u7a0b\u5b58\u5728，\u76d1\u542c\u5957\u63a5\u5b57\u5c31\u4e0d\u4f1a\u5173\u95ed<\/p>\n<\/li>\n
\u53ef\u80fd\u5bfc\u81f4\u540e\u7eed\u65e0\u6cd5\u91cd\u542f\u670d\u52a1（\u7aef\u53e3\u5360\u7528）<\/p>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n
\u7cfb\u7edf\u9650\u5236\u89c4\u907f<\/p>\n
\u6bcf\u4e2a\u8fdb\u7a0b\u6709\u6587\u4ef6\u63cf\u8ff0\u7b26\u6570\u91cf\u9650\u5236（ulimit -n）<\/p>\n<\/li>\n
\u957f\u671f\u8fd0\u884c\u7684\u5b50\u8fdb\u7a0b\u79ef\u7d2f\u672a\u5173\u95ed\u7684\u00a0server_fd\u00a0\u53ef\u80fd\u8017\u5c3d\u8d44\u6e90<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
\u804c\u8d23\u5206\u79bb\u539f\u5219<\/p>\n
\u7236\u8fdb\u7a0b\u4e13\u804c\u63a5\u53d7\u65b0\u8fde\u63a5（accept()）<\/p>\n<\/li>\n
\u5df2\u63a5\u53d7\u7684\u8fde\u63a5\u7531\u5b50\u8fdb\u7a0b\u5168\u6743\u5904\u7406<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
\u5f15\u7528\u8ba1\u6570\u7ba1\u7406<\/p>\n
\u539f\u59cb\u72b6\u6001：<\/p>\n
\u7236\u8fdb\u7a0b\u6301\u6709\u00a0client_fd（\u5f15\u7528\u8ba1\u6570=1）<\/p>\n<\/li>\n
\u5b50\u8fdb\u7a0b\u6301\u6709\u00a0client_fd（\u5f15\u7528\u8ba1\u6570=2）<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
\u7236\u8fdb\u7a0b\u6267\u884c\u00a0close(client_fd)\u00a0\u540e：<\/p>\n
\u5f15\u7528\u8ba1\u6570\u51cf\u4e3a1（\u4ec5\u5b50\u8fdb\u7a0b\u6301\u6709）<\/p>\n<\/li>\n
\u5f53\u5b50\u8fdb\u7a0b\u9000\u51fa\u65f6\u4f1a\u518d\u6b21\u51cf\u4e3a0，\u89e6\u53d1\u771f\u6b63\u5173\u95ed<\/p>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n
\u9884\u9632\u7ade\u6001\u6761\u4ef6<\/p>\n
\u5982\u679c\u7236\u8fdb\u7a0b\u4e0d\u5173\u95ed\u00a0client_fd：<\/p>\n
\u7236\u8fdb\u7a0b\u610f\u5916\u64cd\u4f5c\u8be5\u63cf\u8ff0\u7b26\u53ef\u80fd\u5e72\u6270\u5b50\u8fdb\u7a0b<\/p>\n<\/li>\n
\u7236\u8fdb\u7a0b\u5d29\u6e83\u4f1a\u5bfc\u81f4\u5ba2\u6237\u7aef\u8fde\u63a5\u5f02\u5e38（\u5f15\u7528\u8ba1\u6570\u4e0d\u5f52\u96f6）<\/p>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n
\u590d\u5236<\/p>\n
\u521d\u59cb\u72b6\u6001：
\n\u7236\u8fdb\u7a0b\u6587\u4ef6\u63cf\u8ff0\u7b26\u8868：
\n[0] stdin
\n[1] stdout
\n[2] stderr
\n[3] server_fd –> \u76d1\u542c\u5957\u63a5\u5b57（\u5f15\u7528\u8ba1\u6570=1）<\/p>\n
After accept():
\n\u7236\u8fdb\u7a0b\u65b0\u589e：
\n[4] client_fd –> \u5ba2\u6237\u7aef\u5957\u63a5\u5b57（\u5f15\u7528\u8ba1\u6570=1）<\/p>\n
After fork():
\n\u5b50\u8fdb\u7a0b\u6587\u4ef6\u63cf\u8ff0\u7b26\u8868：
\n[0] stdin
\n[1] stdout
\n[2] stderr
\n[3] server_fd –> \u540c\u4e00\u76d1\u542c\u5957\u63a5\u5b57（\u5f15\u7528\u8ba1\u6570=2）
\n[4] client_fd –> \u540c\u4e00\u5ba2\u6237\u7aef\u5957\u63a5\u5b57（\u5f15\u7528\u8ba1\u6570=2）<\/p>\n
After close()\u64cd\u4f5c：
\n\u7236\u8fdb\u7a0b：
\nclose(4) –> \u5ba2\u6237\u7aef\u5957\u63a5\u5b57\u5f15\u7528\u8ba1\u6570=1
\n\u5b50\u8fdb\u7a0b：
\nclose(3) –> \u76d1\u542c\u5957\u63a5\u5b57\u5f15\u7528\u8ba1\u6570=1 <\/p>\n
\u5047\u8bbe\u6ce8\u91ca\u6389\u8fd9\u4e24\u4e2a\u00a0close()：<\/p>\n
c<\/p>\n
\u590d\u5236<\/p>\n
\/\/ close(server_fd); \/\/ \u5b50\u8fdb\u7a0b\u672a\u5173\u95ed
\n\/\/ close(client_fd); \/\/ \u7236\u8fdb\u7a0b\u672a\u5173\u95ed <\/p>\n
\u76d1\u542c\u5957\u63a5\u5b57\u6cc4\u6f0f<\/p>\n
\u6240\u6709\u5b50\u8fdb\u7a0b\u90fd\u6301\u6709\u00a0server_fd<\/p>\n<\/li>\n
\u5373\u4f7f\u4e3b\u8fdb\u7a0b\u60f3\u5173\u95ed\u670d\u52a1，\u4e5f\u65e0\u6cd5\u771f\u6b63\u91ca\u653e\u7aef\u53e3<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
\u5ba2\u6237\u7aef\u8fde\u63a5\u6cc4\u6f0f<\/p>\n
\u7236\u8fdb\u7a0b\u6301\u7eed\u79ef\u7d2f\u00a0client_fd<\/p>\n<\/li>\n
\u8fbe\u5230\u6587\u4ef6\u63cf\u8ff0\u7b26\u4e0a\u9650\u540e\u65e0\u6cd5\u63a5\u53d7\u65b0\u8fde\u63a5<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
\u8fde\u63a5\u65e0\u6cd5\u6b63\u5e38\u5173\u95ed<\/p>\n
\u5f53\u5b50\u8fdb\u7a0b\u9000\u51fa\u65f6，client_fd\u00a0\u5f15\u7528\u8ba1\u6570\u4ecd\u4e3a1（\u7236\u8fdb\u7a0b\u6301\u6709）<\/p>\n<\/li>\n
\u5ba2\u6237\u7aef\u8fde\u63a5\u4fdd\u6301\u6253\u5f00\u76f4\u5230\u7236\u8fdb\u7a0b\u9000\u51fa<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
\u9632\u5fa1\u6027\u5173\u95ed \u5728\u9519\u8bef\u5904\u7406\u8def\u5f84\u4e2d\u4e5f\u5e94\u6dfb\u52a0\u00a0close()\u00a0\u64cd\u4f5c：<\/p>\n
c<\/p>\n
\u590d\u5236<\/p>\n
if (connect() < 0) {
\n close(fd);
\n \/\/ \u9519\u8bef\u5904\u7406
\n} <\/li>\n
\u73b0\u4ee3\u66ff\u4ee3\u65b9\u6848 \u4f7f\u7528\u00a0fork()\u00a0+\u00a0close()\u00a0\u7684\u4f20\u7edf\u65b9\u5f0f\u4e4b\u5916，\u66f4\u63a8\u8350\u4ee5\u4e0b\u65b9\u5f0f：<\/p>\n
socketpair()\u00a0+\u00a0fd passing（\u9ad8\u7ea7IPC）<\/p>\n<\/li>\n
IO\u591a\u8def\u590d\u7528（select\/poll\/epoll）<\/p>\n<\/li>\n
\u7ebf\u7a0b\u6c60<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
\u8bca\u65ad\u5de5\u5177<\/p>\n
\u4f7f\u7528\u00a0lsof -p [PID]\u00a0\u67e5\u770b\u8fdb\u7a0b\u6301\u6709\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26<\/p>\n<\/li>\n
netstat -tulpn\u00a0\u67e5\u770b\u7aef\u53e3\u5360\u7528\u60c5\u51b5<\/p>\n<\/li>\n
\/proc\/[PID]\/fd\u00a0\u76ee\u5f55\u76f4\u63a5\u89c2\u5bdf\u6587\u4ef6\u63cf\u8ff0\u7b26<\/p>\n<\/li>\n<\/ul>\n<\/li>\n
\u8fd9\u4e24\u4e2a\u00a0close()\u00a0\u64cd\u4f5c\u7684\u672c\u8d28\u662f：<\/p>\n
\u660e\u786e\u8fdb\u7a0b\u804c\u8d23：\u7236\u5b50\u8fdb\u7a0b\u5404\u53f8\u5176\u804c，\u5173\u95ed\u4e0d\u9700\u8981\u7684\u8d44\u6e90\u5f15\u7528<\/p>\n<\/li>\n
\u7cbe\u7ec6\u63a7\u5236\u751f\u547d\u5468\u671f：\u901a\u8fc7\u5f15\u7528\u8ba1\u6570\u673a\u5236\u786e\u4fdd\u8d44\u6e90\u53ca\u65f6\u91ca\u653e<\/p>\n<\/li>\n
\u7cfb\u7edf\u5065\u58ee\u6027\u4fdd\u969c：\u9884\u9632\u8d44\u6e90\u6cc4\u6f0f\u5bfc\u81f4\u7684\u7ea7\u8054\u6545\u969c<\/p>\n<\/li>\n
\u8fd9\u79cd\u6a21\u5f0f\u4f53\u73b0\u4e86UNIX\u54f2\u5b66\u4e2d"\u505a\u4e00\u4ef6\u4e8b\u5e76\u505a\u597d"\u7684\u8bbe\u8ba1\u601d\u60f3，\u662f\u6784\u5efa\u53ef\u9760\u7f51\u7edc\u670d\u52a1\u7684\u57fa\u7840\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u6587\u7ae0\u6d4f\u89c8\u9605\u8bfb1k\u6b21\uff0c\u70b9\u8d5e25\u6b21\uff0c\u6536\u85cf8\u6b21\u3002\u901a\u8fc7\u544a\u8bc9\u5185\u6838"\u7236\u8fdb\u7a0b\u5b8c\u5168\u4e0d\u9700\u8981\u5b50\u8fdb\u7a0b\u7684\u9000\u51fa\u4fe1\u606f"\uff0c\u4f7f\u5f97\u5185\u6838\u81ea\u52a8\u56de\u6536\u7ec8\u6b62\u7684\u5b50\u8fdb\u7a0b\u8d44\u6e90\uff0c\u4ece\u800c\u4ece\u6839\u672c\u4e0a\u907f\u514d\u4e86\u50f5\u5c38\u8fdb\u7a0b\u7684\u4ea7\u751f\u3002\u8fd9\u79cd\u65b9\u5f0f\uff1a\u7b80\u6d01\u9ad8\u6548\uff08\u65e0\u9700\u5faa\u73af\u8c03\u7528wait()\u9002\u5408\u4e0d\u9700\u8981\u6536\u96c6\u5b50\u8fdb\u7a0b\u72b6\u6001\u7684\u573a\u666f\u662f\u73b0\u4ee3Linux\u7cfb\u7edf\u4e2d\u5904\u7406\u50f5\u5c38\u8fdb\u7a0b\u7684\u63a8\u8350\u65b9\u5f0f\u4e4b\u4e00\u8fd9\u4e24\u4e2aclose()\u660e\u786e\u8fdb\u7a0b\u804c\u8d23\uff1a\u7236\u5b50\u8fdb\u7a0b\u5404\u53f8\u5176\u804c\uff0c\u5173\u95ed\u4e0d\u9700\u8981\u7684\u8d44\u6e90\u5f15\u7528\u7cbe\u7ec6\u63a7\u5236\u751f\u547d\u5468\u671f\uff1a\u901a\u8fc7\u5f15\u7528\u8ba1\u6570\u673a\u5236\u786e\u4fdd\u8d44\u6e90\u53ca\u65f6\u91ca\u653e\u7cfb\u7edf\u5065\u58ee\u6027\u4fdd\u969c\uff1a\u9884\u9632\u8d44\u6e90\u6cc4\u6f0f\u5bfc\u81f4\u7684\u7ea7\u8054\u6545\u969c\u8fd9\u79cd\u6a21\u5f0f\u4f53\u73b0\u4e86UNIX\u54f2\u5b66\u4e2d"\u505a\u4e00\u4ef6\u4e8b\u5e76\u505a\u597d"\u7684\u8bbe\u8ba1\u601d\u60f3\uff0c\u662f\u6784\u5efa\u53ef\u9760\u7f51\u7edc\u670d\u52a1\u7684\u57fa\u7840\u3002<\/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":[58,43,78],"topic":[],"class_list":["post-15002","post","type-post","status-publish","format-standard","hentry","category-server","tag-linux","tag-43","tag-78"],"yoast_head":"\n