Fix for issue fmtlib#3241

Signed-off-by: Vladislav Shchapov <[email protected]>
phprus · Dec 23, 2022 · 2a0c98c · 2a0c98c
1 parent 6a186bc
commit 2a0c98c
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Showing 2 changed files with 5 additions and 1 deletion.
diff --git a/include/fmt/core.h b/include/fmt/core.h
@@ -863,7 +863,7 @@ template <typename Char, typename T, typename U,
 FMT_CONSTEXPR auto copy_str(T* begin, T* end, U* out) -> U* {
   if (is_constant_evaluated()) return copy_str<Char, T*, U*>(begin, end, out);
   auto size = to_unsigned(end - begin);
-  memcpy(out, begin, size * sizeof(U));
+  if (size > 0) memcpy(out, begin, size * sizeof(U));
   return out + size;
 }
 

diff --git a/test/format-test.cc b/test/format-test.cc
@@ -2047,6 +2047,10 @@ TEST(format_test, to_string) {
 #if FMT_USE_FLOAT128
   EXPECT_EQ(fmt::to_string(__float128(0.5)), "0.5");
 #endif
+
+#if defined(FMT_USE_STRING_VIEW) && FMT_CPLUSPLUS >= 201703L
+  EXPECT_EQ(fmt::to_string(std::string_view()), "");
+#endif
 }
 
 TEST(format_test, output_iterators) {