From 172b031a50d6d9bd95a12fc7116c6e6f3b07ac3d Mon Sep 17 00:00:00 2001
From: denchat <19730041+denchat@users.noreply.github.com>
Date: Sat, 17 Apr 2021 21:39:57 +0700
Subject: [PATCH] Suppressing clang complain "forward declaration"

Clang complains about "forward declaration of template entity" of all basic_data<>'s members that do not have definitions in `format.h`

```
C:/Users/User/AppData/Roaming/fmt-master/include\fmt/format.h:956:25: warning: instantiation of variable 'fmt::detail::basic_data<>::powers_of_10_64' required here, but no definition is available [-Wundefined-var-template]
  static const uint64_t powers_of_10_64[];
                        ^
C:/Users/User/AppData/Roaming/fmt-master/include\fmt/format.h:956:25: note: forward declaration of template entity is here
C:/Users/User/AppData/Roaming/fmt-master/include\fmt/format.h:956:25: note: add an explicit instantiation declaration to suppress this warning if 'fmt::detail::basic_data<>::powers_of_10_64' is explicitly instantiated in another translation unit
```
---
 include/fmt/format.h | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/include/fmt/format.h b/include/fmt/format.h
index cbb0a766..270f118a 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -3887,6 +3887,29 @@ extern template int snprintf_float<long double>(long double value,
                                                 int precision,
                                                 float_specs specs,
                                                 buffer<char>& buf);
+extern template const uint64_t basic_data<void>::powers_of_10_64[];
+extern template const uint32_t basic_data<void>::zero_or_powers_of_10_32_new[];
+extern template const uint64_t basic_data<void>::zero_or_powers_of_10_64_new[];
+extern template const uint64_t basic_data<void>::grisu_pow10_significands[];
+extern template const int16_t basic_data<void>::grisu_pow10_exponents[];
+extern template const divtest_table_entry<uint32_t> basic_data<void>::divtest_table_for_pow5_32[];
+extern template const divtest_table_entry<uint64_t> basic_data<void>::divtest_table_for_pow5_64[];
+extern template const uint64_t basic_data<void>::dragonbox_pow10_significands_64[];
+extern template const uint128_wrapper basic_data<void>::dragonbox_pow10_significands_128[];
+#if !FMT_USE_FULL_CACHE_DRAGONBOX
+extern template const uint64_t basic_data<void>::powers_of_5_64[];
+extern template const uint32_t basic_data<void>::dragonbox_pow10_recovery_errors[];
+#endif
+// GCC generates slightly better code for pairs than chars.
+extern template const basic_data<void>::digit_pair basic_data<void>::digits[];
+extern template const char basic_data<void>::foreground_color[];
+extern template const char basic_data<void>::background_color[];
+extern template const char basic_data<void>::reset_color[5];
+extern template const wchar_t basic_data<void>::wreset_color[5];
+extern template const char basic_data<void>::signs[];
+// DEPRECATED! These are for ABI compatibility.
+extern template const uint32_t basic_data<void>::zero_or_powers_of_10_32[];
+extern template const uint64_t basic_data<void>::zero_or_powers_of_10_64[];
 }  // namespace detail
 #endif