C scanning directory: qsort

qsort.c

/*
  http://www.scs.stanford.edu/histar/src/pkg/uclibc/test/stdlib/qsort.c

  gcc -o qsort qsort.c -Wall
*/

#include <stdio.h>
#include <dirent.h>
#include <stdlib.h>  // /usr/include/stdlib.h:764:13: note: expected ‘__compar_fn_t’ but argument is of type ‘int (*)(const struct dirent **, const struct dirent **)’
#include <unistd.h>

static int select_files(const struct dirent *dirbuf)
{
    if (dirbuf->d_name[0] == '.')
        return 0;
    else
        return 1;
}

int main(void)
{
    struct dirent **array;
    struct dirent *dirbuf;

    int i, numdir;

/*  The scandir() function reads the directory dirname and builds an array 
    of pointers to directory entries, using malloc() to allocate the space.
    You can deallocate the memory allocated for the array by calling free().
    Free each pointer in the array, and then free the array itself.       */

    chdir("/");

 // 1: scandir only
    numdir = scandir(".", &array, select_files, NULL);
    printf("\nGot %d entries from scandir().\n", numdir);

    for (i = 0; i < numdir; ++i) {
        dirbuf = array[i];
        printf("[%.2d] %s\n", i, dirbuf->d_name);
        free(array[i]);
    }
    free(array);

 // 2a: scandir + alphasort
    numdir = scandir(".", &array, select_files, alphasort);
    printf("\nGot %d entries from scandir() using alphasort().\n", numdir);
    for (i = 0; i < numdir; ++i) {
        dirbuf = array[i];
        printf("[%.2d] %s\n", i, dirbuf->d_name);
    }

 // 2b, array is not freed yet: qsort (+ alphasort)
    printf("\nCalling qsort()\n");
    qsort(array, numdir, sizeof(struct dirent *), alphasort);  // int (*)(const struct dirent **, const struct dirent **)

    for (i = 0; i < numdir; ++i) {
        dirbuf = array[i];
        printf("[%.2d] %s\n", i, dirbuf->d_name);
        free(array[i]);
    }
    free(array);

    return (0);
}