Update isfinite declaration to be constexpr for c++23 only

Fix fmtlib#3745
hchataing · Dec 9, 2023 · 2b23e4e · 2b23e4e
1 parent dee0dbf
commit 2b23e4e
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Showing 3 changed files with 8 additions and 2 deletions.
diff --git a/include/fmt/core.h b/include/fmt/core.h
@@ -113,6 +113,12 @@
 #  define FMT_CONSTEXPR20
 #endif
 
+#if (FMT_CPLUSPLUS >= 202302L)
+#  define FMT_CONSTEXPR23 constexpr
+#else
+#  define FMT_CONSTEXPR23
+#endif
+
 // Check if constexpr std::char_traits<>::{compare,length} are supported.
 #if defined(__GLIBCXX__)
 #  if FMT_CPLUSPLUS >= 201703L && defined(_GLIBCXX_RELEASE) && \

diff --git a/include/fmt/format.h b/include/fmt/format.h
@@ -2750,7 +2750,7 @@ struct has_isfinite<T, enable_if_t<sizeof(std::isfinite(T())) != 0>>
 
 template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value&&
                                         has_isfinite<T>::value)>
-FMT_CONSTEXPR20 bool isfinite(T value) {
+FMT_CONSTEXPR23 bool isfinite(T value) {
   constexpr T inf = T(std::numeric_limits<double>::infinity());
   if (is_constant_evaluated())
     return !detail::isnan(value) && value < inf && value > -inf;

diff --git a/test/format-test.cc b/test/format-test.cc
@@ -91,7 +91,7 @@ template <typename Float> void check_isfinite() {
   EXPECT_TRUE(isfinite(Float(fmt::detail::max_value<double>())));
   // Use double because std::numeric_limits is broken for __float128.
   using limits = std::numeric_limits<double>;
-  FMT_CONSTEXPR20 auto result = isfinite(Float(limits::infinity()));
+  FMT_CONSTEXPR23 auto result = isfinite(Float(limits::infinity()));
   EXPECT_FALSE(result);
   EXPECT_FALSE(isfinite(Float(limits::infinity())));
   EXPECT_FALSE(isfinite(Float(-limits::infinity())));