undefined reference

[ollii]

Hello everybody
im creating a srever program for my work
that can communicate with the client using udp protocol.

i get couple errors and i do not know hat those error mean and what is the problem with by code.
Need Help

The code:

#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <time.h>
#include <netdb.h>
#include <sys/signal.h>
#include <string.h> //for strln()
#include <sys/types.h>
#include <fcntl.h>


#define EOB "Client:$$"
#define KB_size 80
#define MAX_CLIENT 100
int ClientNo = 0;

////////////////////////////////////////////
int openService (int NoClients)
{int sock;
int intPort;
char host[80];
char KB_buff[KB_size];

sock = sockTCP_create();
printf("Enter port: ");
fgets(KB_buff, KB_size, stdin);
intPort = atoi(KB_buff);
sock_bind(sock, intPort);
sock_listen(sock, NoClients);
gethostname(host,80);
printf("ITserver at %s [ %d]\n",
host,intPort);
return (sock);
}
////////////////////////////////////////////
int getClient(MSsock)
{char *cli_name;
struct sockaddr_in *client_EP;

int sock;
char *msg =
"Type any string or EOB to quit\n";
time_t con_time;

sock = sock_accept(MSsock, &client_EP);
if (sock == 0) IO_error (0, "accept");
else {
time(&con_time);
writeMessage(sock, msg);
ClientNo += 1;
cli_name = (char *)getNameByEP (*client_EP);
printf ("Client %d (%s-%d)\n", ClientNo,
cli_name, client_EP->sin_port);
printf (" -->connect at %s\n",
asctime (localtime (&con_time)));
}
return (sock);
}
////////////////////////////////////////////
int DST_SingEcho (int sock,char *msg)
// Get a message at sock, if message <> EOB
// echo back, else B or "" then quit;
{
int nc;
int quit = 0;

nc = readMessage (sock,msg);
quit = (strncmp(msg,EOB, 9) == 0);
if(quit==0)
return 0;
return nc;
}

////////////////////////////////////////////
int main()
{
int MS_socket,MS_UDP,
CS_socket[MAX_CLIENT],CS_udp[MAX_CLIENT],i,iRet,iMaxSock=0;
struct sockaddr_in servaddr, cliaddr[MAX_CLIENT];
time_t cli_time;
fd_set fdRead;
struct timeval tv = {1,1};
char sRecvMsg[1024];

memset((char*)CS_socket,0,sizeof(int)*MAX_CLIENT);
memset((char*)CS_udp,0,sizeof(int)*MAX_CLIENT);
MS_socket = openService (0);
MS_UDP = open_UDP();
while (1)
{
FD_ZERO(&fdRead);

FD_SET(MS_socket,&fdRead);
iMaxSock = MS_socket;

for(i=0;i<MAX_CLIENT;i++)
{
if(CS_socket[i] >0)
{
fcntl(CS_socket[i], F_SETFL, O_NONBLOCK);
iMaxSock = (iMaxSock > CS_socket[i])?iMaxSock:CS_socket[i];
FD_SET(CS_socket[i],&fdRead);
}
}
tv.tv_sec =1;
tv.tv_usec = 0;
iRet = select( iMaxSock +1,&fdRead,NULL,NULL,&tv);
if(iRet==0)
continue;
else if(iRet >0)
{
if(FD_ISSET(MS_socket,&fdRead))
{
CS_socket[i] = getClient(MS_socket,cliaddr[i]);
}

for(i=0;i<MAX_CLIENT;i++)
{
if((CS_socket[i] > 0) && (FD_ISSET(CS_socket[i],&fdRead)))
{
//recv
memset(sRecvMsg,0,sizeof(sRecvMsg));
if(DST_SingEcho(CS_socket[i],sRecvMsg) ==0)
{
close(CS_socket[i]);
CS_socket[i]=0;
}
//multicast
for(i=0;i<MAX_CLIENT;i++)
{
if(CS_socket[i] > 0)
{
sendtoDST (cliaddr[i],CS_udp,sRecvMsg);
}
}
}
}
}

}
return 1;
}





the error code that im getting is:

gcc -o server_it server_it.c DST_sock.o
/tmp/cckBqZJJ.o(.text+0x281): In function `main':
server_it.c: undefined reference to `open_UDP'
collect2: ld returned 1 exit status

[gpraghuram]

Hi,
I think the error u get is because u havent included the UDP library while compiling.
The syntax is gcc *.c -l<udplibrary> -o <>
Note:Plese add code tags before posting.

Thanks
Raghuram

[JosAH]

i get couple errors and i do not know hat those error mean and what is the problem with by code.

the error code that im getting is:

gcc -o server_it server_it.c DST_sock.o
/tmp/cckBqZJJ.o(.text+0x281): In function `main':
server_it.c: undefined reference to `open_UDP'
collect2: ld returned 1 exit status

Your program tries to call the function open_UDP() but the linker found that there
isn't any. The linker (collect2) complains about it ('ld' is just the frontend of the
linker called by the compiler). You have to supply it a library that contains that function.

kind regards,

Jos

edit: may you and this guy can work together.