How to include macro in struct - c

Question

I am trying to find a way to dynamically access a certain macro in C.
I tried to include the macro in the struct but then I get the "initializer element is not constant" error. Basically I just want to access the correct macro based on an index but I just don't know how. Is there a straight forward way of accomplishing this? Please note the code is not complete but only an illustration of what I want to do.
#define Data_CAN_SES_Enbl() (...)
#define Data_CAN_SAS_Enbl() (...)
#define Data_CAN_PEP_Enbl() (...)
struct CAN_Rx {
const uint8 id;
const uint8 bus;
xx
};
static struct CAN_Rx CheckRx[] = {
/* SES */
{
0,0,?
},
/* SAS */
{
1,0,?
},
/* PEP */
{
2,1,?
}
};
void run(uint8 index)
{
uint8 enabled = CheckRx[index].xx;
}

Answer 1

Simply put: you won't.
Dont think of macros as code: they're just chunk of text replaced by the preprocessor before compiling your code.
If you need to embed code in a struct, you better look at function pointers.
--- EDIT ---
By the way, why you want to use macro in your code? Looking at it, it seems you cand do the same thing with a simple function returning a struct with a different content based on a parameter, like:
static struct CAN_Rx getCANrx(int index){
switch(index)
{
case '0':
struct CAN_rx res = /* initialize struct */;
return res;
case '1':
/* as previous */
default:
/* manage default result or errors */
}
}

Answer 2

Maybe you can go with function pointers?
#include <stdio.h>
int Data_CAN_SES_Enbl() { return 0; }
int Data_CAN_SAS_Enbl() { return 1; }
int Data_CAN_PEP_Enbl() { return 2; }
struct CAN_Rx {
const int id;
const int bus;
int (*xx)();
};
static struct CAN_Rx CheckRx[] = {
/* SES */
{
0,0,Data_CAN_SES_Enbl
},
/* SAS */
{
1,0,Data_CAN_SAS_Enbl
},
/* PEP */
{
2,1,Data_CAN_PEP_Enbl
}
};
int run(int index)
{
int enabled = (*CheckRx[index].xx)();
return enabled;
}
int main() {
printf("%d\n",run(0));
}

Answer 3

If you are curious see below macro example.
For your case , macro cant be better than function pointers.
Using macro just for fun at your case.
#include <stdio.h>
#include <stdlib.h>
#define Data_CAN_SES_Enbl(Y,Z) Y+Z
#define Data_CAN_SAS_Enbl(Y,Z) Y*Z
#define Data_CAN_PEP_Enbl(Y,Z) Y-Z
#define Str(X) #X
#define Data_CAN_Enbl(X,Y,Z) Data_CAN_##X##_Enbl(Y,Z);
#define SES 1
#define SAS 2
#define PEP 3
struct CAN_Rx {
int id;
int bus;
int Flag;
};
static struct CAN_Rx CheckRx[] = {
/* SES */
{
0,100,SES
},
/* SAS */
{
70,20,SAS
},
/* PEP */
{
100,50,PEP
}
};
void run(int index)
{
int RRR=0;
switch(CheckRx[index].Flag){
case SES:
RRR=Data_CAN_Enbl(SES,CheckRx[index].id,CheckRx[index].bus);
printf("%s :%d\n",_Str(SES),RRR);
break;
case SAS:
RRR=Data_CAN_Enbl(SAS,CheckRx[index].id,CheckRx[index].bus);
printf("%s :%d\n",_Str(SAS),RRR);
break;
case PEP:
RRR=Data_CAN_Enbl(PEP,CheckRx[index].id,CheckRx[index].bus);
printf("%s :%d\n",_Str(PEP),RRR);
break;
}
}
int main(){
run(0);
run(1);
run(2);
printf("%d\n",CheckRx[0].Flag);
return 0;
}