rok commented on code in PR #51216: URL: https://github.com/apache/arrow/pull/51216#discussion_r4040047948
########## cpp/src/arrow/util/chrono_config_internal.h: ########## @@ -0,0 +1,56 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +#pragma once + +#include <chrono> + +// Share backend selection with the vendored implementation without including its +// headers. datetime.h undefines macros needed when compiling the implementation. +// +// On Windows, MSVC's standard library uses the system timezone database, while +// libstdc++ reads tzdata files (using TZDIR). Libraries without the C++20 timezone +// APIs, including older libc++, still require the vendored date library. +// +// Use the standard backend by default. Builds may explicitly define +// ARROW_USE_STD_CHRONO to 0 or 1 when they need to select a backend. +// +// Automatically disable the default for libraries without the C++20 timezone APIs. +// On non-Windows, older libstdc++ versions also need the fallback because of +// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116110 (fully fixed in GCC 16.2). +// Check library macros, not __GNUC__, so Clang using libstdc++ agrees with GCC. Review Comment: Removed. ########## cpp/src/arrow/util/chrono_config_internal.h: ########## @@ -0,0 +1,56 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +#pragma once + +#include <chrono> + +// Share backend selection with the vendored implementation without including its +// headers. datetime.h undefines macros needed when compiling the implementation. +// +// On Windows, MSVC's standard library uses the system timezone database, while +// libstdc++ reads tzdata files (using TZDIR). Libraries without the C++20 timezone +// APIs, including older libc++, still require the vendored date library. +// +// Use the standard backend by default. Builds may explicitly define +// ARROW_USE_STD_CHRONO to 0 or 1 when they need to select a backend. +// +// Automatically disable the default for libraries without the C++20 timezone APIs. Review Comment: Rewrote the paragraph. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
