Explanation of use of Linux C select function

The code is simple to send the C language to send HTTP requests, but i= read (SOCKFD, buf, BUFSIZE-1); can run normally,

Replace with i= Read (SOCKFD, buf, BUFSIZE-1); After the program exits, do not know what reason, to seek answers.

#include <stdio.h> #include <sys/socket.h> #include <sys/types.h> #include <time.h> #include <errno.h> #include <signal.h> #include <stdlib.h> #include <string.h> #include <unistd.h > #include <sys/wait.h> #include <sys/time.h> #include <netinet/in.h> #include <arpa/inet.h    > #define IPSTR "180.97.33.107" #define PORT 80#define BUFSIZE 1024x768 * 2int Read (int fd, char *buf, int count) {    int nread, Totlen = 0;        while (Totlen! = count) {nread = Read (FD, buf, Count-totlen);        if (nread = = 0) return totlen;         if (nread = =-1) return-1;        Totlen + = Nread;    BUF + = Nread; } return Totlen;}        int main (int argc, char **argv) {int SOCKFD, ret, I, H;        struct sockaddr_in servaddr;        Char str1[4096], buf[bufsize];        Socklen_t Len;        Fd_set T_set1;         struct Timeval TV; if ((SOCKFD = socket (af_inet, sock_stream, 0)) < 0){printf ("---socket error!\n");        Exit (0);         };        Bzero (&servaddr, sizeof (SERVADDR));        servaddr.sin_family = af_inet;        Servaddr.sin_port = htons (port);                if (Inet_pton (Af_inet, Ipstr, &servaddr.sin_addr) <= 0) {printf ("--inet_pton error!\n");        Exit (0);         }; if (Connect (SOCKFD, (struct sockaddr *) &servaddr, sizeof (SERVADDR)) < 0) {printf ("Connect error!\n")                ;        Exit (0);        } memset (str1, 0, 4096);        strcat (str1, "get/http/1.1\n");        strcat (str1, "host:www.baidu.com\n");        strcat (str1, "\ n");         printf ("%s", str1);        ret = Write (Sockfd,str1,strlen (str1));                if (Ret < 0) {printf ("errno =%d strerror =%s\n", errno, Strerror (errno));        Exit (0);        }else{printf ("Send%d size\n", ret);        } fd_zero (&AMP;T_SET1);         Fd_set (SOCKFD, &t_set1);           while (1) {     Tv.tv_sec= 2;                tv.tv_usec= 0;                H= 0;                printf ("--------------->1\n");                H= Select (sockfd +1, &t_set1, NULL, NULL, &AMP;TV); printf ("--------------->2\n");                printf ("H ===================%d\n", h);                if (h = = 0) continue;                        if (H < 0) {close (SOCKFD);p rintf ("Select Error \ n");                return-1;                        } if (H > 0) {memset (buf, 0, BUFSIZE);                        I= Read (SOCKFD, buf, BUFSIZE-1);                        I= Read (SOCKFD, buf, BUFSIZE-1);p rintf ("I ==========================%d", i);                                if (i==0) {close (SOCKFD);p rintf ("Stop ... ... \ n"););                        return-1;                } printf ("%s\n", buf);        }} close (SOCKFD); return 0;}

Explanation of use of Linux C select function