scandir(dirname, namelist, select, compar)
struct direct *(*namelist);
struct direct **d1, **d2;
Scandir reads the directory dirname and builds an array of pointers to directory entries using malloc(3). It returns the number of entries
in the array and a pointer to the array through namelist.
The select parameter is a pointer to a user supplied subroutine which is called by scandir to select which entries are to be included in
the array. The select routine is passed a pointer to a directory entry and should return a non-zero value if the directory entry is to be
included in the array. If select is null, then all the directory entries will be included.
The compar parameter is a pointer to a user supplied subroutine which is passed to qsort(3) to sort the completed array. If this pointer is
null, the array is not sorted. Alphasort is a routine which can be used for the compar parameter to sort the array alphabetically.
The memory allocated for the array can be deallocated with free (see malloc(3)) by freeing each pointer in the array and the array itself.