Availability:C-language interface function
hash_table_t PL_new_hash_table(int
size, void (*free_symbol)(void *n, void *v))Create a new table for size key-value pairs. The table is
resized when needed. If you know the table will hold 10,000 key-value
pairs, providing a suitable initial size avoids resizing. The free_symbol
function is called whenever a key-value pair is removed from the table.
This can be NULL.