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 20 namespace absl { 21 ABSL_NAMESPACE_BEGIN 22 23 // This global mutex protects on-demand construction of flag objects in MSVC 24 // builds. 25 #if defined(_MSC_VER) && !defined(__clang__) 26 27 namespace flags_internal { 28 29 ABSL_CONST_INIT static absl::Mutex construction_guard(absl::kConstInit); 30 GetGlobalConstructionGuard()31absl::Mutex* GetGlobalConstructionGuard() { return &construction_guard; } 32 33 } // namespace flags_internal 34 35 #endif 36 37 ABSL_NAMESPACE_END 38 } // namespace absl 39