Weijie Zhang ---> thank you, I found it and it looks like this is the program I've been looking for. Unfortunately, it's
 quite complicated ;) like for me, at the class we haven't written such complex programs. For example, this is a program
 which send messages from client to server:


#include <stdlib.h>
#include <sys/neutrino.h>

#define SIZE 32

struct {
	int type; 				
	char text[SIZE]; 		
	} 

msg, rmsg;

main() {

	int child, res,i,pid, status;
	int chid,con;
	
	//Utworzenie kanalu
	chid = ChannelCreate(_NTO_CHF_DISCONNECT);

	//Tworzenie procesu potomnego
	if ((child = fork()) == 0) { 	
	// Kod klienta ------------------------------------
	printf("Proces potomny utworzony\n");
    pid = getppid();
    
    //Klient dolacza sie do kanalu chid procesu pid
    con = ConnectAttach(0,pid,chid,0,0);
    if(con>=0) {
    	printf("Proces potomny - polaczenie %d\n",con);
    } 
    else {
    perror("Polaczenie"); exit(1);
    }

    for(i=0; i<10; i++) {
    
    sprintf(msg.text,"K - %d",i);
    printf("Klient - wyslane: %s \n", msg.text);
    MsgSend(con,&msg,sizeof(msg),&rmsg,sizeof(rmsg));
    printf("Klient - odebrane: %s \n",rmsg.text);
    sleep(1);
    };
    exit(0);
	}
	
	//Kod serwera ---------------------------------------
	printf("Serwer startuje \n");
	for(i=0; i<11; i++) {
	pid = MsgReceive(chid,&msg,sizeof(msg),NULL);
	printf("Serwer - odebrane %s \n", msg.text);
	sprintf(msg.text,"potwierdzenie %d",i+1);
	res = MsgReply(pid,0,&msg,sizeof(msg));
	}
	pid = wait(&status);
}

Anyway ;) - I need to modify time1.c program a little bit. 

Once again, thanks.

Regards