diff --git a/usql.cpp b/usql.cpp
index 518c622..7ac76d3 100644
--- a/usql.cpp
+++ b/usql.cpp
@@ -304,7 +304,7 @@ std::unique_ptr<ValueNode> USql::pp_function(const std::vector<std::unique_ptr<V
 
 	if (parsed_value->node_type == NodeType::int_value || parsed_value->node_type == NodeType::float_value) {
 		std::string format = evaluatedPars.size() > 1 ? evaluatedPars[1]->getStringValue() : "";
-		char buf[16] {0};
+		char buf[20] {0};	// TODO constant here
 		double value = parsed_value->getDoubleValue();
 
 		if (format == "100%")