1 // 2 // Copyright 2019 The Abseil Authors. 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // https://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 16 #include "absl/flags/flag.h" 17 18 #include "absl/base/config.h" 19 #include "absl/flags/internal/commandlineflag.h" 20 #include "absl/flags/internal/flag.h" 21 22 namespace absl { 23 ABSL_NAMESPACE_BEGIN 24 25 // This global mutex protects on-demand construction of flag objects in MSVC 26 // builds. 27 #if defined(_MSC_VER) && !defined(__clang__) 28 29 namespace flags_internal { 30 31 ABSL_CONST_INIT static absl::Mutex construction_guard(absl::kConstInit); 32 GetGlobalConstructionGuard()33absl::Mutex* GetGlobalConstructionGuard() { return &construction_guard; } 34 35 } // namespace flags_internal 36 37 #endif 38 39 ABSL_NAMESPACE_END 40 } // namespace absl 41