In POSIX, there are two sets of functions related to directories. The first set, `opendir()` (open a directory for reading), `readdir()` (return next filename

In POSIX, there are two sets of functions related to directories. The first set, `opendir()` (open a directory for reading), `readdir()` (return next filename upon each call) and `closedir()` (close the directory). `readdir()` does not guarantee an ordering of filenames and any filtering must be done by the application. Then there's `wordexp()` and `wordfree()`. The first takes a file glob (file pattern?) and returns an array of filenames matching the pattern. Any memory allocated by `wordexp()` is freed by calling `wordfree()`. Both have their uses.