socket编程API总结

一、代码注释

1.

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <netinet/in.h>
#define SERVPORT 3333
#define BACKLOG 10
#define MAX_CONNECTED_NO 10
#define MAXDATASIZE 5

int main()
{
        struct sockaddr_in server_sockaddr,client_sockaddr;
        int sin_size,recvbytes;
        int sockfd,client_fd;
        char buf[MAXDATASIZE];
        if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1){
                perror("socket");
                exit(1);
        }
        printf("socket success!,sockfd=%d\n",sockfd);
        server_sockaddr.sin_family=AF_INET;
        server_sockaddr.sin_port=htons(SERVPORT);
        server_sockaddr.sin_addr.s_addr=INADDR_ANY;
        bzero(&(server_sockaddr.sin_zero),8);
        if(bind(sockfd,(struct sockaddr *)&server_sockaddr,sizeof(struct sockaddr))==-1){
                perror("bind");
                exit(1);
        }
        printf("bind success!\n");
        if(listen(sockfd,BACKLOG)==-1){
                perror("listen");
                exit(1);
        }
        printf("listening....\n");
        if((client_fd=accept(sockfd,(struct sockaddr *)&client_sockaddr,&sin_size))==-1){
                perror("accept");
                exit(1);
        }
        if((recvbytes=recv(client_fd,buf,MAXDATASIZE,0))==-1){
                perror("recv");
                exit(1);
        }
        printf("received a connection :%s\n",buf);
        close(sockfd);
}