diff --git a/xpath.c b/xpath.c
index f445ed2..9683832 100644
--- a/xpath.c
+++ b/xpath.c
@@ -1240,6 +1240,7 @@
     xmlXPathObjectPtr obj;
     xmlNodeSetPtr ret;
 
+    if (ctxt == NULL) return(NULL);
     if (ctxt->value == NULL) {
 	xmlXPathSetError(ctxt, XPATH_INVALID_OPERAND);
 	return(NULL);