[danielchen37]

dear all:
i come across a udf problem. the case ran well without the udfs. but when the udfs were compiled, built and loaded, the error signal would appear and the interation would not process a bit.
here is the error signal:

Error:
FLUENT received fatal signal (ACCESS_VIOLATION)
1. Note exact events leading to error.
2. Save case/data under new name.
3. Exit program and restart to continue.
4. Report error to your distributor.
Error Object: ()

the udfs are compiled and loaded successfully as:
xforce.c
yforce.c
zforce.c
uds.c
Generating Code...
# Generating udf_names.c because of makefile xforce.obj yforce.obj zforce.obj uds.obj
udf_names.c
# Linking libudf.dll because of makefile user_nt.udf udf_names.obj xforce.obj yforce.obj zforce.obj uds.obj
Microsoft (R) Incremental Linker Version 6.00.8168
Copyright (C) Microsoft Corp 1992-1998. All rights reserved.
Creating library libudf.lib and object libudf.exp
Done.
"E:/hyc/hyc/RE1000"
Opening library "E:\hyc\hyc\RE1000\libudf"...
Library "E:\hyc\hyc\RE1000\libudf\ntx86\3d\libudf.dll" opened
xforce_source
yforce_source
zforce_source
uds_source
Done.

and here is one code of my udfs and the rest of the udfs all share with the same structure:
#include"udf.h"
#include"mem.h"
#include"metric.h"
DEFINE_SOURCE(xforce_source,c,t,dS,eqn)
{
real dens;
real u;
real v;
real w;
real ux;
real uy;
real uz;
real cp;
real A;
real con;
real tx;
real tgx;
real source;
real x[ND_ND];
real ur;
real sc;
real sp;
C_CENTROID(x,c,t);
dens=C_R(c,t);
u=C_U(c,t);
v=C_V(c,t);
w=C_W(c,t);
ux=C_DUDX(c,t);
uy=C_DUDY(c,t);
uz=C_DUDZ(c,t);
A=C_UDSI(c,t,0);
tx=C_T_G(c,t)[0];
con=-0.02;
ur=v*uy+u*uz;
sc=dens*ur+con*A*tx;
sp=dens*ux;
source=sp*u+sc;
dS[eqn]=sp;
return source;
}

please tell me what's wrong with my udf and how could i correct it.
thank you!