(PHP 4, PHP 5 <= 5.0.5)
cpdf_save_to_file — Writes the pdf document into a file
Outputs the PDF document into a file if it has been created in memory.
This function is not needed if the PDF document has been open by specifying a filename as a parameter of cpdf_open().
The document handle, returned by cpdf_open().
The path to the saved PDF document
如果成功则返回 TRUE，失败则返回 FALSE。