Function projectm_playlist_insert_path 

pub unsafe extern "C" fn projectm_playlist_insert_path(
    instance: projectm_playlist_handle,
    path: *const c_char,
    index: u32,
    recurse_subdirs: bool,
    allow_duplicates: bool,
) -> u32

@brief Inserts presets from the given path to the end of the current playlist.

This method will scan the given path for files with a “.milk” extension and add these to the playlist.

Symbolic links are not followed.

@param instance The playlist manager instance. @param path A local filesystem path to scan for presets. @param index The index to insert the presets at. If it exceeds the playlist size, the presets are added at the end of the playlist. @param recurse_subdirs If true, subdirectories of the given path will also be scanned. If false, only the exact path given is searched for presets. @param allow_duplicates If true, files found will always be added. If false, only files are added that do not already exist in the current playlist. @return The number of files added. 0 may indicate issues scanning the path.