int cpdf_open(int compression, string filename);The cpdf_open() function opens a new pdf document. The first parameter turns document compression on if it is unequal to 0. The second optional parameter sets the file in which the document is written. If it is omitted the document is created in memory and can either be written into a file with the cpdf_save_to_file() or written to standard output with cpdf_output_buffer().
Note: The return value will be needed in futher versons as the first parameter in all other functions writing to the pdf document.
The ClibPDF library takes the filename "-" as a synonym for stdout. If PHP is compiled as an apache module this will not work because the way ClibPDF outputs to stdout does not work with apache.
See also cpdf_close().