How to use realloc in a function in C

Question

Building on what I learned here: Manipulating dynamic array through functions in C.

void test(int data[])
{
    data[0] = 1;    
}    

int main(void)
{    
         


        

Answer 1

You want to modify the value of an int* (your array) so need to pass a pointer to it into your increase function:

void increase(int** data)
{
    *data = realloc(*data, 5 * sizeof int);
}

Calling code would then look like:

int *data = malloc(4 * sizeof *data);
/* do stuff with data */
increase(&data);
/* more stuff */
free(data);