在linux中，惊群现象已经消失了的，我们可以看 http://simohayha.javaeye.com/blog/561424 ，但是当我们在开发服务器时候，需要使用epoll，发现一个问题，就是当一个请求过来的时候，发现有的时候被唤起的进程不止一个，看下面的程序:#include <sys/socket.h>
#include <sys/epoll.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <pthread.h>
#include <errno.h>
#include <unistd.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <errno.h>
#define KEY 1234
#define SIZE 1024
#define PORT 9999
#define MAXFDS 5000
#define EVENTSIZE 100
void process();
int fd, cfd,opt=1;
int shmid;
char *shmaddr;
struct shmid_ds buf;
int num = 0 ;
int main(int argc, char *argv[])
{
shmid = shmget(KEY,SIZE,IPC_CREAT|0600); /* 建立共享内存 */
if(shmid == -1){
printf("create share memory failed\n");
}
shmaddr = (char *)shmat(shmid,NULL,0);
if(shmaddr == (void *)-1){
printf("connect to the share memory failed: %s",strerror(errno));
return 0;
}
strcpy(shmaddr,"1\n");
struct sockaddr_in sin, cin;
socklen_t sin_len = sizeof(struct sockaddr_in);
if ((fd = socket(AF_INET, SOCK_STREAM, 0)) <= 0)
{
fprintf(stderr, "socket failed\n");
return -1;
}
memset(&sin, 0, sizeof(struct sockaddr_in));
sin.sin_family = AF_INET;
sin.sin_port = htons((short)(PORT));
sin.sin_addr.s_addr = INADDR_ANY;
if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)) != 0)
{
fprintf(stderr, "bind failed\n");
return -1;
}
if (listen(fd, 32) != 0)
{
fprintf(stderr, "listen failed\n");
return -1;
}
int i ;
for(i = 0; i < 2; i++)
{
int pid = fork();
if(pid == 0)
{
