CFD Online Discussion Forums - problem with printf and Massage

hi guys,
im writing a UDF that should be compiled and not interpret, and i know that when i want to print something to consol i should use "Massage" instead of "printf" , but the problem is when i use "Massage" i face with an unsuall error by compiler that says:

newmotion.obj : error LNK2019: unresolved external symbol Massage referenced in ...
libudf.dll : fatal error LNK1120: 1 unresolved externals

but when i use printf there is no such error when compiling but nothing is shown in the consol,
Does anyone have any idea to help me get around this problem,
tnx

here is the udf just in case it may help:

#include "udf.h"
#include "sg.h"
static real y = 0;
static int i = 0;
real avg;

DEFINE_CG_MOTION(Disk, dt, vel, omega, time, dtime)
{
Thread *t;
face_t f;
real x[ND_ND];
NV_S(vel, =, 0);
NV_S(omega, =, 0);
t = DT_THREAD(dt);

begin_f_loop(f,t)
{
F_CENTROID(x,f,t);
y = y + x[1];
i = i + 1;
}
end_f_loop(f,t)

avg = y * (1./i);
Massage("dis: %g \n",avg);

if (avg > -0.0645)
vel[1] = (-1)*time*9.81;
else
vel[1] = 0;
}