实现高并发服务器三种简化模型 线程 进程 IO复用

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<errno.h>
#include<netinet/in.h>
#define SERV_PORT 3000
#define MAXLINE 1024
void str_echo(int sockfd)
{
ssize_t n;
char buf[MAXLINE];
again:
while( (n= read(sockfd, buf ,MAXLINE)) > 0)
write(sockfd, buf, n);
if(n<0 && errno == EINTR)
goto again;
else if(n<0)
printf("stro_echo:read error\n");
}

void main(void)
{
int lfd, cfd;
struct sockaddr_in serv_addr, clin_addr;
socklen_t clin_len;
char buf[MAXLINE];
pid_t childpid;
lfd = socket(AF_INET, SOCK_STREAM, 0);
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(SERV_PORT);
bind(lfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
listen(lfd, 128);
for(;;){
clin_len = sizeof(clin_addr);
cfd = accept(lfd,(struct sockaddr*) &clin_addr, &clin_len);
if( (childpid = fork()) == 0){
close(lfd);
str_echo(cfd);
exit(0);
}
close(cfd);
}
}

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<errno.h>
#include<netinet/in.h>
#include<pthread.h>
#define SERV_PORT 3000
#define MAXLINE 1024
static void *str_echo(void *sockfd)
{
ssize_t n;
char buf[MAXLINE];
again:
while( (n= read((int)(sockfd), buf ,MAXLINE)) > 0)
write((int)(sockfd), buf, n);
if(n<0 && errno == EINTR)
goto again;
else if(n<0)
printf("stro_echo:read error\n");
close((int)sockfd);
}

void main(void)
{
int lfd, cfd;
struct sockaddr_in serv_addr, clin_addr;
socklen_t clin_len;
char buf[MAXLINE];
pid_t childpid;
lfd = socket(AF_INET, SOCK_STREAM, 0);
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(SERV_PORT);
bind(lfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
listen(lfd, 128);
for(;;){
clin_len = sizeof(clin_addr);
cfd = accept(lfd,(struct sockaddr*) &clin_addr, &clin_len);
pthread_t tid;
pthread_create(&tid, NULL, &str_echo,(void *) cfd);
}
close(lfd);
}

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<sys/epoll.h>
#include<errno.h>
#include<netinet/in.h>
#define SERV_PORT 3000
#define MAXLINE 1024
void str_echo(int sockfd)
{
ssize_t n;
char buf[MAXLINE];
again:
while( (n= read(sockfd, buf ,MAXLINE)) > 0)
write(sockfd, buf, n);
if(n<0 && errno == EINTR)
goto again;
else if(n<0)
printf("stro_echo:read error\n");
}
void main(void)
{
int lfd, cfd, efd;
struct sockaddr_in serv_addr, clin_addr;
socklen_t clin_len;
char buf[MAXLINE];
int len, n;
struct epoll_event tep, ep[1024];
lfd = socket(AF_INET, SOCK_STREAM, 0);
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(SERV_PORT);
bind(lfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
listen(lfd, 128);
efd = epoll_create(1024);
tep.events = EPOLLIN;
tep.data.fd = lfd;
epoll_ctl(efd, EPOLL_CTL_ADD, lfd, &tep);
for(;;){
n = epoll_wait(efd, ep, 1024, -1);
int  i = 0;
for( i =0;i<n;i++){

clin_len = sizeof(clin_addr);
cfd = accept(lfd,(struct sockaddr*) &clin_addr, &clin_len);
str_echo(cfd);
close(cfd);
}
}
close(lfd);
}