error about uds in udf
 

Hi, I have such udf that use uds :
uds is a temperature quantity and it's unit is kelvin. I see error when I compile it. Please, help me to solve the error

#include "udf.h"
#define h 2.0
DEFINE_SOURCE(energy_source,c,t,dS,eqn)
{
real temp, source, phi;
temp=C_T(c,t);
phi=UDSI(c,t,0);
source = h*(phi-temp);
dS[eqn] = -h;
return source;
}