How can I make for loop of #define function? - c

Question

I have #define function with argument such as DEF_GLOBAL_STRUCT(index) and I need to call this macro from 1 to 100. What is the best way? Can I use for loop?
I made the simple code to show my problem.
#include <stdio.h>
#include <stdint.h>
#define DEF_GLOBAL_STRUCT(index) uint8_t m_##index##_size=2; \
uint32_t m_##index##_data1=0; \
uint32_t m_##index##_data2=0;
DEF_GLOBAL_STRUCT(1)
DEF_GLOBAL_STRUCT(2)
DEF_GLOBAL_STRUCT(3)
// ...
DEF_GLOBAL_STRUCT(100)
int main()
{
printf("%u\n", m_1_size);
return 0;
}
Instead of 100 lines of define function call, can I use something like for loop. Or is there any other solution?
If I have all the control of the code I can define structure and declare it with array. But I can't do it. I need to use this type of define function. That is my limitation.

Answer 1

Your question is asking if you can mix C language with Preprocessor directives to automate the generation of code using both C language and Preprocessor directives.
The answer is not in the way you are trying to do it because of how the Preprocessor and the C compiler work.
The Preprocessor is a separate step from compilation. The idea is that the Preprocessor does a text replacement step of the C source code file to generate a new, temporary version of the C source code file which is then compiled by the C compiler.
It is two different steps and first the Preprocessor does its work and then the C compiler does its work.
What I would suggest is to write a simple program that generates an include file that contains the list of definitions you want to use. Then in the place where you want to put those definitions, use the #include directive to include it at that point.
So if you have a simple script or perhaps a C program something like:
#include <stdio.h>
int main ()
{
int i;
for (i = 1; i <= 100; i++) printf ("DEF_GLOBAL_STRUCT(%d)\n", i);
return 0;
}
Then you compile it and run it from a command line redirecting the output as in:
mygen >junk.h
then in the place you need these directives:
#include <stdio.h>
#include <stdint.h>
#define DEF_GLOBAL_STRUCT(index) uint8_t m_##index##_size=2; \
uint32_t m_##index##_data1=0; \
uint32_t m_##index##_data2=0;
#include "junk.h"
int main()
{
printf("%u\n", m_1_size);
return 0;
}

Answer 2

You can save some typing by defining another macro:
#include <stdio.h>
#include <stdint.h>
#define DEF_GLOBAL_STRUCT(index) uint8_t m_##index##_size=2; \
uint32_t m_##index##_data1=0; \
uint32_t m_##index##_data2=0;
#define DEF_GLOBAL_STRUCT_DECADE(tens) \
DEF_GLOBAL_STRUCT(tens##0) \
DEF_GLOBAL_STRUCT(tens##1) \
DEF_GLOBAL_STRUCT(tens##2) \
DEF_GLOBAL_STRUCT(tens##3) \
DEF_GLOBAL_STRUCT(tens##4) \
DEF_GLOBAL_STRUCT(tens##5) \
DEF_GLOBAL_STRUCT(tens##6) \
DEF_GLOBAL_STRUCT(tens##7) \
DEF_GLOBAL_STRUCT(tens##8) \
DEF_GLOBAL_STRUCT(tens##9)
DEF_GLOBAL_STRUCT(1)
DEF_GLOBAL_STRUCT(2)
DEF_GLOBAL_STRUCT(4)
DEF_GLOBAL_STRUCT(5)
DEF_GLOBAL_STRUCT(6)
DEF_GLOBAL_STRUCT(7)
DEF_GLOBAL_STRUCT(8)
DEF_GLOBAL_STRUCT(9)
DEF_GLOBAL_STRUCT_DECADE(1)
DEF_GLOBAL_STRUCT_DECADE(2)
DEF_GLOBAL_STRUCT_DECADE(3)
DEF_GLOBAL_STRUCT_DECADE(4)
DEF_GLOBAL_STRUCT_DECADE(5)
DEF_GLOBAL_STRUCT_DECADE(6)
DEF_GLOBAL_STRUCT_DECADE(7)
DEF_GLOBAL_STRUCT_DECADE(8)
DEF_GLOBAL_STRUCT_DECADE(9)
DEF_GLOBAL_STRUCT(100)
int main()
{
printf("%u\n", m_1_size);
return 0;
}