Function svn_prop_is_svn_prop 

pub unsafe extern "C" fn svn_prop_is_svn_prop(
    prop_name: *const c_char,
) -> svn_boolean_t

Return @c TRUE iff @a prop_name represents the name of a Subversion property. That is, any property name in Subversion’s name space for versioned or unversioned properties, regardless whether the particular property name is recognized.