Function xmlXPathCompareValues 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn xmlXPathCompareValues(
    ctxt: *mut c_void,
    inf: c_int,
    strict: c_int,
) -> c_int

int xmlXPathCompareValues(xmlXPathParserContextPtr ctxt, int inf, int strict).

inf/strict encode the operator: <=(1,1), <==(1,0), >=(0,1), >==(0,0). Returns the comparison result without pushing (upstream callers push the boolean themselves).

SAFETY

• ctxt 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.