return pointer from a C function is good/bad design? [closed]

Question

I want to know if return pointer from a C function is good/bad design? If it is a bad practice, what would be a good practice in the following example:

The question is a continued part of: c function return static variable

in data.h file:

#include <stdio.h>
#include <stdlib.h> 

typedef struct
{
   int age;
   int number;
} person;

person * getPersonInfo();

in data.c

#include "data.h"
static struct person* person_p = NULL;

person * getPersonInfo()
{
   person_p = (struct person*)malloc(10 * sizeof(struct person));
   return person_p;
}

in main.c

#include "data.h"

int main()
{
   person* pointer = getPersonInfo();
   return 0;
}

basically, the main function in main file needs to get the value of all the elements of array which is pointed by static pointer person_p, if it is not a good practice, then what a good practice should be?

Answer 1

The only reason it is bad is because you don't have any memory managing structure behind it. In your current code, you have a memory leak because you allocate a person struct via malloc() but do not free it.

Consider writing a wrapper function that handles that memory management for you like so:

void freePerson(struct person * personToDelete)
{
    free(personToDelete);
}

Then in your main:

int main()
{
   person* pointer = getPersonInfo();
   freePerson(pointer); // After you are done using it
   return 0;
}

I also have to warn against casting the results of malloc(). In my experience it can result in undefined behavior.