(PHP 3 >= 3.0.8, PHP 4, PHP 5 <= 5.0.4)
Closes the PDF document.
This should be the last function called, even after cpdf_finalize(), cpdf_output_buffer() or cpdf_save_to_file().
pdf_document
The document handle, returned by cpdf_open().
如果成功则返回 TRUE，失败则返回 FALSE。