XSLT (PHP 4)
PHP Manual

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

XSLT_OPT_SILENT (integer)
Drop all logging and error reporting. This is a generic option for all backends that may be added in the future.
XSLT_SABOPT_PARSE_PUBLIC_ENTITIES (integer)

Tell Sablotron to parse public entities. By default this has been turned off.

XSLT_SABOPT_DISABLE_ADDING_META (integer)

Do not add the meta tag "Content-Type" for HTML output. The default is set during compilation of Sablotron.

XSLT_SABOPT_DISABLE_STRIPPING (integer)
Suppress the whitespace stripping (on data files only).
XSLT_SABOPT_IGNORE_DOC_NOT_FOUND (integer)
Consider unresolved documents (the document() function) non-lethal.
XSLT_SABOPT_FILES_TO_HANDLER (integer)
XSLT_ERR_UNSUPPORTED_SCHEME (integer)
Error return code, for scheme handlers.

XSLT (PHP 4)
PHP Manual