Description:
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The PHP manual describes pdf_open_file as working with just one argument (the pdf handle).

This code works fine with PHP 4 but on PHP 5.0.0 does not work. It thinks that the 'filename' argument is required, but it is in fact optional.

Reproduce code:
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$pdf = pdf_new();
pdf_open_file($pdf);

Expected result:
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It should work without an error. Should create a PDF document in memory, not in a file.

Actual result:
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Fatal error: Uncaught exception 'PDFlibException' with message 'pdf_open_file() expects exactly 2 parameters, 1 given' in C:\test.php:2 Stack trace: #0 {main} thrown in C:\test.php on line 2