How do I return a pointer to an array from my function in C?

Question

Sorry there are many similar questions but I just can't work out what I'm doing wrong (amateur alert!).

I'm trying to fill two arrays within a function then get the information back in main. I declare the arrays in main but need to assign them memory in the function (which works out how big they should be). Although the arrays seem to fill fine and I can print them from within the function, I get a segmentation fault when I try to print them from main.

I've tried to troubleshoot in this simplified program with a function that fills one array - it has the same problem. I assume I'm stuffing up my pointers - what am I doing wrong?? Here is the code and the output:

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

void *make_v(double num, double *v)
{
        int i;
        v = (double *)calloc(5,sizeof(double));
        for (i=0; i<5; i++) {
                num += 5;
                v[i] = num;
        }

        printf("IN: ");
        for (i=0; i<5; i++)
                printf("%lf ", v[i]);
        printf("\n");
}

main(int argc,char **argv)
{
        double *v=NULL;
        double num=10.0;
        int i;

        make_v(num, v);

        printf("OUT:\nv:[");
        for (i=0; i<5; ++i) {
                printf("%lf ", v[i]);
        }
}

This outputs: IN: 15.000000 20.000000 25.000000 30.000000 35.000000 OUT: Segmentation fault

I'm coding in linux if that makes a difference...

Hope someone can help, thanks!

Answer 1

double *make_v(double num)
{
    int i;
    v = (double *)calloc(5,sizeof(double));
    for (i=0; i<5; i++) {
            num += 5;
            v[i] = num;
    }

    printf("IN: ");
    for (i=0; i<5; i++)
            printf("%lf ", v[i]);
    printf("\n");
    retrun v;
}