diff --git a/src/php_arma.hh b/src/php_arma.hh
index 17b09e0..db5ca26 100644
--- a/src/php_arma.hh
+++ b/src/php_arma.hh
@@ -65,10 +65,13 @@
 
 /// Helper macros for parameter parsing.
 
-#ifndef Z_PARAM_DOUBLE_DEREF
+#if PHP_VERSION_ID >= 70200
 #define Z_PARAM_DOUBLE_DEREF(dest)                        \
     Z_PARAM_DOUBLE_EX2(dest, _dummy, 0, 1, 0)
-#endif // !Z_PARAM_DOUBLE_DEREF
+#else
+// Before PHP 7.2, parameter is dereferenced by default here.
+#define Z_PARAM_DOUBLE_DEREF Z_PARAM_DOUBLE
+#endif
 
 #ifdef PHP_ARMA_OPERATORS