Function xmlSchematronValidateOneElement 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn xmlSchematronValidateOneElement(
    ctxt: *mut c_void,
    elem: *mut _xmlNode,
) -> c_int

Validate a single element against the schema (upstream xmlSchematronValidateOneElement); 0 if valid, -1 on error.

SAFETY

• ctxt, elem must be valid pointers (or NULL where the upstream C contract allows), obtained from the matching constructor/owner and not yet freed; the callee may take or keep ownership exactly as the C API specifies.

The caller must not race this call with concurrent mutation of the same objects from other threads (per-object state is not internally synchronized). Violating any of the above is undefined behavior.

Exercised by the C-API differential courts (courts/suites/data-abi/*-family-probe.c) and the CLI differential courts; those pass byte-for-byte against the upstream oracle.