下列常量由此扩展定义，且仅在此扩展编译入 PHP 或在运行时动态载入时可用。
XSL_CLONE_AUTO
(int)
XSL_CLONE_NEVER
(int)
XSL_CLONE_ALWAYS
(int)
LIBXSLT_VERSION
(int)
libxslt version like 10117.
LIBXSLT_DOTTED_VERSION
(string)
libxslt version like 1.1.17.
LIBEXSLT_VERSION
(int)
libexslt version like 813.
LIBEXSLT_DOTTED_VERSION
(string)
libexslt version like 1.1.17.
XSL_SECPREF_NONE
(int)
Deactivate all security restrictions.
XSL_SECPREF_READ_FILE
(int)
Disallows reading files.
XSL_SECPREF_WRITE_FILE
(int)
Disallows writing files.
XSL_SECPREF_CREATE_DIRECTORY
(int)
Disallows creating directories.
XSL_SECPREF_READ_NETWORK
(int)
Disallows reading network files.
XSL_SECPREF_WRITE_NETWORK
(int)
Disallows writing network files.
XSL_SECPREF_DEFAULT
(int)
Disallows all write access, i.e. a bitmask of
XSL_SECPREF_WRITE_NETWORK |
XSL_SECPREF_CREATE_DIRECTORY |
XSL_SECPREF_WRITE_FILE.