define array length struct with global constant from other file

In my model I have quite some parameters that are used by a lot of different functions. To make changing settings easy, I want to use one file for all my paramaters, keeping it sepperate from any of the "real programming".
That file is called parameters.c
In it, all parameters are defined like:

#define N 1000
#define T 1373

In a different c file (MyLib.c), I create a struct type:

typedef struct Model{
  struct Element el[N];
};

both files are included in my main script using:

#include "parameters.c"
#include "MyLib.c"

The project can not be build this way. However, if I move the line

#define N 1000

from parameters.c to MyLib.c, it works.
I could just create the struct to have an array that is larger than any N value I'd use, but that doesn't seem like the correct way to do it.

Is there a correct way to implement this, or would I indeed have to create the large array? (in the comments it was said the definition of correct is too broad. In this instance I mean memory efficient. I don't want to allocate a much larger chunck of memory than I need to.)

Thanks in advance.

Solution

Is there a correct way to implement this

You library may look like this:

// parameters.h
#ifndef PARAMETERS_H_
#define PARAMETERS_H_

// documentation
#define PARAMETERS_COUNT_OF_ELEMENTS    1000
// this parameters does that and that
#define PARAMETERS_DESCRIPTIVE_NAME     1373
//      ^^^^^^^^^^^ - consistent namespace naming

#endif

// mylib.h - safe yourself trouble and DoN'T mIx UppErCaSe with lOwErcAsE
// escapecially in header names
// subjectively, I do not like pascal case - snake case rule them all!
#ifndef MYLIB_H_
#define MYLIB_H_
#include "parameters.h"
#include "element.h" // for struct element

/// This structure represents a model in our library.
struct mylib_model {
   //  ^^^^^^ - consistent namespace naming

   /// These are super important elements we deeply care about.
   struct element el[PARAMETERS_COUNT_OF_ELEMENTS];

};

/**
 * @brief this function does that and that
 * @return 0 on success, otherwise error
 *
 * Write documentation keeping consistent style, for example
 * use doxygen.
 */
int mylib_do_something(struct mylib_model *the_model);

#endif

// mylib.c
#include "mylib.h"

int mylib_do_something(struct mylib_model *t) {
     // do something here
     // return 0 on success, otherwise document error codes, or use the ones from errno.h
     return 0;
}

// main.c
#include "mylib.h"
int main() {
    struct mylib_model model = {0};
    int err = mylib_do_something(&model);
    if (err != 0) { abort(); }
    return 0;
}

Your parmeters.h is very similar to the way autoconf projects generate config.h present in many GNU projects. Many projects use a configuration file, sometimes generate automatically by a build system. Nowadays if choosing build automation software I would recommend cmake. Other links: kernel coding style and google coding style.