reuseaddr_eserver.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define TRUE 1
#define ERROR 0

void error_handling(char *message);

int main(int argc, char const *argv[])
{
	int serv_sock, clnt_sock;
	char message[30] ;//= "I am AllenZF";
	int option, str_len;
    socklen_t optlen, clnt_adr_sz;
    struct sockaddr_in serv_adr, clnt_adr ;

    if(argc != 2){
    	printf("Usage : %s <port>\n", argv[0]);
    	exit(1);
    }

    serv_sock = socket(PF_INET, SOCK_STREAM, 0);
    if(serv_sock == -1)
    	error_handling("socket() error");

    /*
    optlen = sizeof(option);
    option = TRUE;
    setsockopt(serv_sock, SOL_SOCKET, SO_REUSEADDR, (void *)&option, optlen);
    */

    memset(&serv_adr, 0, sizeof(serv_adr));
    serv_adr.sin_family = AF_INET;
    serv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
    serv_adr.sin_port = htons(atoi(argv[1]));

    if(bind(serv_sock, (struct sockaddr*)&serv_adr, sizeof(serv_adr)))
    	error_handling("bind() error");
    if(listen(serv_sock, 5) == -1)
    	error_handling("listen() error");
    clnt_adr_sz = sizeof(clnt_adr);
    clnt_sock = accept(serv_sock, (struct sockaddr*)&clnt_adr, &clnt_adr_sz);

    while((str_len = read(clnt_sock, (void *)message, sizeof(message))) != 0){
    	write(clnt_sock, (void *)message, str_len);
    	write(1, (void *)message, str_len);
    }

    close(clnt_sock);
    close(serv_sock);
	return 0;
}

void error_handling(char *message)
{
	fputs(message, stderr);
	fputc('\n', stderr);
	exit(1);
}