Open an existing paradox database file. The actual file has to be opened before with fopen(). The first parameter is the return value of px_new(). This function can also be used to open primary index files and tread them like a paradox database. This is supported for those who would like to investigate a primary index. It cannot be used to accelerate access to a database file. Returns FALSE on failure.
See also example at px_new(), fopen().