[ns] It happened to be wrong to bind the right C++ variable in a structure in my code

[Siyui AliOh]

It happened to be wrong to bind the right C++ variable in a structure
in my code, will it work?
I have written some c and h files in my ns, and i must bind
corresponding c variables with tcl variables to let it run correctly.
In ns manual, the bindings are such as:

ASRMAgent::ASRMAgent() {
      bind("pdistance_", &pdistance_);
      ...
      ...
}

while in my code, the c variable is in a structure:

class TailYaw : public VecPosition {
public:
       ......
protected:
       ...
       struct TOT   tot;
   ...
};
......
TailYaw::TailYaw(......){
       ......
       bind("damaging_", &tot.surface.pu);
       ......
       }

I believe it will run well, but when i make my ns, some error
infomation come out:

bmspu/bmvecinpu.cc:165: no matching function for call to `
  TailYaw::bind(const char[10], unsigned char*)'
/user/ns/ns-allinone-2.26/tclcl-1.0b13/tclcl.h:174: candidates are:
void
  TclObject::bind(const char*, TracedInt*)
/user/ns/ns-allinone-2.26/tclcl-1.0b13/tclcl.h:175:
void
  TclObject::bind(const char*, TracedDouble*)
/user/ns/ns-allinone-2.26/tclcl-1.0b13/tclcl.h:176:
void
  TclObject::bind(const char*, double*)
/user/ns/ns-allinone-2.26/tclcl-1.0b13/tclcl.h:179:
void
  TclObject::bind(const char*, unsigned int*)
/user/ns/ns-allinone-2.26/tclcl-1.0b13/tclcl.h:180:
void
  TclObject::bind(const char*, int*)
/user/ns/ns-allinone-2.26/tclcl-1.0b13/tclcl.h:182:
void
  TclObject::bind(const char*, TclObject**)
/user/ns/ns-allinone-2.26/tclcl-1.0b13/tclcl.h:185:
void
  TclObject::bind(const char*, int64_t*)

so many candidates it give to me, all the candidates are not indicated
to my structure.
I have tried to bind an int variable in my code, it work,
so something must have been happened when i bind a variable in c strucuture