Libcurl offers a wildcard matching functionality, which allows a callback (set with `CURLOPT_CHUNK_BGN_FUNCTION`) to return information back to libcurl on how to handle a specific entry in a directory when libcurl iterates over a list of all available entries. When this callback returns `CURL_CHUNK_BGN_FUNC_SKIP`, to tell libcurl to not deal with that file, the internal function in libcurl then calls itself recursively to handle the next directory entry. If there's a sufficient amount of file entries and if the callback returns "skip" enough number of times, libcurl runs out of stack space. The exact amount will of course vary with platforms, compilers and other environmental factors.