Arduino Pass by reference

arduino_code3.c

typedef struct
{
  int data;
}st_struct;

void my_fn(void *st)
{
  st_struct *s = (st_struct *)st;
  ...
}

void setup()
{
  ...
}

void loop()
{
  ...
}

arduino_code4.c

#include "arduino_code_st.h"

void my_fn(st_struct *st)
{
  
}

void setup()
{
  
}

void loop()
{
  
}

arduino_code_st.h

//File path ARDUINO_LIBRARY/arduino_code_st/arduino_code_st.h

typedef struct
{
  int data;
}st_struct;