Silly question [Easy]

[SoullessKnightX]

Trying to add in some channels and I'm working on the channel list.
However, I'm having a little bit of a problem...
I want it to show up only to level 60's...here is my current code
if (IS_IMMORTAL(ch))
    {
      send_to_char("IMP channel    ",ch);
      if(!IS_SET(ch->comm,COMM_NOIMP))
        send_to_char("ON\n\r",ch);
      else
        send_to_char("OFF\n\r",ch);
    }

I have replaced IS_IMMORTAL with the following (They all didn't work)
level_imp
IMPLEMENTOR
IS_IMPLEMENTOR
level = 60
max_level
IS_IMP
LEVEL_IMP

I think that is it.
Gives me the same warning:
gcc -c -Wall -O -ggdb  act_comm.c
act_comm.c: In function `do_channels':
act_comm.c:108: warning: implicit declaration of function `LEVEL_IMP'
rm -f rom
gcc -O -ggdb -o rom act_comm.o act_enter.o act_info.o act_move.o act_obj.o 
act_t
act_comm.o: In function `do_channels':
/home/badger/fastrom/src/act_comm.c:108: undefined reference to `LEVEL_IMP'
make: *** [rom] Error 1

Thanks