/* chatserver.c */#include <stdlib.h>#include <stdio.h>#include <cnaiapi.h>#define BUFFSIZE		256#define INPUT_PROMPT		"Input_$> "#define RECEIVED_PROMPT		"Received:> "int recvln(connection, char *, int);int readln(char *, int);int main(int argc, char *argv[]) {      char *msg="The author of this program is iFreeBSD (version 1.0)\n" ;	connection	conn;	int		len;	char		buff[BUFFSIZE];      printf(msg) ;	if (argc != 2) {		fprintf(stderr, "usage: %s <appnum>\n", argv[0]);		exit(1);	}	printf("OK!Now Waiting For Connection.\n");	conn = await_contact((appnum) atoi(argv[1]));	if (conn < 0)		exit(1);	        printf("Connection Established.\n");			while((len = recvln(conn, buff, BUFFSIZE)) > 0) {		 printf(RECEIVED_PROMPT);		 fflush(stdout);		 write(STDOUT_FILENO, buff, len);						 printf(INPUT_PROMPT);		 fflush(stdout);		if ((len = readln(buff, BUFFSIZE)) < 1)			break;		buff[len - 1] = '\n';	      send(conn, buff, len, 0);	}		send_eof(conn);	printf("\nClosed.Bye!\n");	return 0;}