From dca553ed968a0b4bd217943c2d58f563a55ae116 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johel=20Ernesto=20Guerrero=20Pe=C3=B1a?=
 <johelegp@gmail.com>
Date: Sun, 21 Feb 2021 17:52:35 -0400
Subject: [PATCH] example: fix compilation for Clang 13

---
 src/include/units/quantity_io.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/include/units/quantity_io.h b/src/include/units/quantity_io.h
index 615882eb..70290bd2 100644
--- a/src/include/units/quantity_io.h
+++ b/src/include/units/quantity_io.h
@@ -36,7 +36,7 @@ void to_stream(std::basic_ostream<CharT, Traits>& os, const quantity<D, U, Rep>&
 {
   os << q.count();
   constexpr auto symbol = detail::unit_text<D, U>();
-  if constexpr (symbol.standard().size()) {
+  if constexpr (bool(symbol.standard().size())) {
     os << " " << symbol.standard();
   }
 }