TinyOS nesC - typedef nx_struct dependence

Question

I have a problem when i create a header file where i define three struct! The problem is a dependence between the struct. I try this like-c syntax but I receive an error when I compile the code.

The error is:

/home/user/top/t2_cur/tinyos-2.x/tos/platforms/telosb/mac/tkn154/timer/Alarm32khzTo62500hzTransformC.nc:53:2: warning: #warning "Warning: MAC timing is not standard compliant!" make: * [exe0] Error 1

This is my code:

#define PRECISION nx_float
typedef nx_struct neurA neuronA;
typedef nx_struct neurB neuronB;
typedef nx_struct neurC neuronC;

nx_struct neurB{
  neurA in[2];
  neurC out;

 PRECISION trans_value;
 PRECISION prop_value;
 PRECISION delta;

 PRECISION in_weight[2];
 PRECISION out_weight[1];
}

nx_struct neurA{
  neurB out[3];

  PRECISION trans_value;
  PRECISION delta;
  PRECISION out_weight[3]; 
}

nx_struct neurC{
 neurB in;

 PRECISION trans_value;
 PRECISION prop_value;
 PRECISION delta;

 PRECISION in_weight;
}

The struct neurB declares at its inside the variables neurC and neurB. If i put the declaration of neurB struct above all other struct in the code, the error is caused by the neurC struct that at its inside declare neurb variable. If I invert the declaration of struct the problem persists with another cause.

I have also try in this way:

  typedef nx_struct neurA{
      neurB out[3];

      PRECISION trans_value;
      PRECISION delta;
      PRECISION out_weight[3]; 
    }neurA;

    typedef nx_struct neurC{
     neurB in;

     PRECISION trans_value;
     PRECISION prop_value;
     PRECISION delta;

     PRECISION in_weight;
    }neurC;

    typedef nx_struct neurB{
      neurA in[2];
      neurC out;

     PRECISION trans_value;
     PRECISION prop_value;
     PRECISION delta;

     PRECISION in_weight[2];
     PRECISION out_weight[1];
    }neurB;

Answer 1

Sometimes error messages are strange and incomprehensible, I dont know the headers surrounding this and if this could be the case. Try with something simple like

typedef struct Point {
    int x;
    int y;
} Point;

Point vPoint;

substituting Your own types into the program one at a time

I think, looking at the above, that You need to have typedeffed the neurA like the Point above before using it.

Answer 2

TinyOS error messages often don't show the exact reason of an error. However, your code is definitely incorrect in at least two aspects.

Firstly, defining neurC having neurB and neurB having neurC is a recursive dependency that can't be compiled. You probably want to use pointers as fields:

typedef struct neurC {
    neurB *in;
} neurC;

Secondly, as you noticed, you can't use neurB before its definition. The solution is to declare it at the beginning and define a structure later. To avoid confusion, I name actual types different way than structures (types' names end with _t). The example for two structures is:

typedef struct neurB neurB_t; // declaration of neurB_t as struct neurB

typedef struct neurC {
    neurB_t *in; // neurB_t is declared before, so it can be used here
} neurC_t;

struct neurB { // definition of struct neurB
    neurC_t *out; // neurC_t is declared before
};