This function returns the path name of a file involved in a drag and drop operation. You typically call this routine from a drop_file_over callback the first time the callback is called for a particular drag and drop operation. If more than one file is being dropped, then you must call this routine multiple times to obtain information about all of the files. You should only call this function once for each file during a single drag and drop operation.

The num argument is the number of the file for which you want to return the path name. The first file is 1. The function returns a null string if there is no file available.