Fixed bug when putting int64_t

bus/m_epics_ca.tpp

@@ -574,7 +574,8 @@ int mEpicsCa<T>::put(V *value) {
         // it as a double. This means we have some loss of precision for large
         // integers, but it is the best we can do ...
         if (ca_field_type(_pChanID) == DBF_DOUBLE) {
-            return putRaw<S>(static_cast<double>(*value));
+            double dval = static_cast<double>(*value);
+            return putRaw<S>(&dval);
         } else {
             return putRaw<S>(value);
         }

test/m_epics_ca_test.cxx

@@ -298,6 +298,14 @@ int main() {
             EQUAL(status, CM_SUCCESS);
             EQUAL(int_val, new_int_val);
 
+            // Write an int64 to a record and read it to check
+            int64_t new_int64_val = 1111;
+            status = int64_ca.put(&new_int64_val);
+            EQUAL(status, CM_SUCCESS);
+            status = int64_ca.get(&int64_val);
+            EQUAL(status, CM_SUCCESS);
+            EQUAL(int64_val, new_int64_val);
+
             // Write to the limit field of the longin record
             new_int_val = 40;
             status = int_hopr_ca.put(&new_int_val);