#3312: fix two sqlite3 crashes.
diff --git a/Modules/_sqlite/module.c b/Modules/_sqlite/module.c
index ceec418..7640e92 100644
--- a/Modules/_sqlite/module.c
+++ b/Modules/_sqlite/module.c
@@ -147,6 +147,7 @@
 {
     PyTypeObject* type;
     PyObject* caster;
+    int rc;
 
     if (!PyArg_ParseTuple(args, "OO", &type, &caster)) {
         return NULL;
@@ -159,7 +160,9 @@
         pysqlite_BaseTypeAdapted = 1;
     }
 
-    microprotocols_add(type, (PyObject*)&pysqlite_PrepareProtocolType, caster);
+    rc = microprotocols_add(type, (PyObject*)&pysqlite_PrepareProtocolType, caster);
+    if (rc == -1)
+        return NULL;
 
     Py_INCREF(Py_None);
     return Py_None;