[SOLVED] Указатели и динамические массивы в С

  int *num_mol_agl;
  for (i=from; i<to+1; i++)
  {
/* здесь рабочий блок, объявление каких то переменный, в т.ч. и num_mol */
    if (i == from)
    {
      agl = (int *) malloc (num_mol * num_mol * sizeof (int));
      connect = (int *) malloc (num_mol * num_mol * sizeof (int));
      num_mol_agl = (int *) malloc (num_mol * sizeof (int));
      stat = (int *) malloc (num_mol * sizeof (int));
      stat_all = (int *) malloc (num_mol * sizeof (int));
    }
/* продолжение */
  }
  num_mol_agl[num_mol-1] = num_mol;
  printf ("%i - %i\n", num_mol-1, num_mol_agl[num_mol-1]);
//   free memory
  free (agl);
  free (connect);
  free (coords);
  free (crit);
  free (label_mol);
//   memory crash here
  free (num_mol_agl);
//   free (stat);
//   free (stat_all);
  free (true_label_mol);
  free (type_atoms);
  return 0;

printf ("%i - %i\n", num_mol-1, num_mol_agl[num_mol]);

num_mol_agl = (int *) malloc (250 * sizeof (int));

num_mol_agl[num_mol-1] = num_mol;
printf ("%i - %i\n", num_mol-1, num_mol_agl[num_mol-1]);

249 - 250
/* текст ошибки */

num_mol_agl = (int *) malloc (2 * sizeof (int));
/* */

num_mol_agl = (int *) realloc (num_mol_agl, num_mol * sizeof (int));

if (num_mol_agl == NULL)
{
  printf ("Memory error (error code: 17)\n");
  return 17;
}

valgrind -q --log-file=valgrind.log ./statgen -i oct-clb -s 1,1 -c 35.747,35.747,35.747 -a 1 -r 0-0:4.55 -o test.dat -l test.log -q

==4529== Syscall param write(buf) points to uninitialised byte(s)
==4529==    at 0x520A1D0: __write_nocancel (in /usr/lib/libc-2.17.so)
==4529==    by 0x51A5352: _IO_file_write@@GLIBC_2.2.5 (in /usr/lib/libc-2.17.so)
==4529==    by 0x51A4A12: new_do_write (in /usr/lib/libc-2.17.so)
==4529==    by 0x51A6184: _IO_do_write@@GLIBC_2.2.5 (in /usr/lib/libc-2.17.so)
==4529==    by 0x51A5B1F: _IO_file_close_it@@GLIBC_2.2.5 (in /usr/lib/libc-2.17.so)
==4529==    by 0x519A567: fclose@@GLIBC_2.2.5 (in /usr/lib/libc-2.17.so)
==4529==    by 0x404E82: summary_statistic (in /home/arcanis/Documents/github/moldyn/stat_new/statgen)
==4529==    by 0x4020DA: main (in /home/arcanis/Documents/github/moldyn/stat_new/statgen)
==4529==  Address 0x4023089 is not stack'd, malloc'd or (recently) free'd

int summary_statistic (char *filename, int step, int num_mol, const int *type_agl, const int *stat_all)

error = reading_coords (filename, type_inter, label_atom, cell, &num_mol,
                            &num_atoms, true_label_mol, label_mol, type_atoms, coords);

a = atoi (&string[n]);