tvl-depot/absl/flags/declare.h
Abseil Team 12bc53e031 Export of internal Abseil changes
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c99f979ad34f155fbeeea69b88bdc7458d89a21c by Derek Mauro <dmauro@google.com>:

Remove a floating point division by zero test.

This isn't testing behavior related to the library, and MSVC warns
about it in opt mode.

PiperOrigin-RevId: 285220804

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68b015491f0dbf1ab547994673281abd1f34cd4b by Gennadiy Rozental <rogeeff@google.com>:

This CL introduces following changes to the class FlagImpl:
* We eliminate the CommandLineFlagLocks struct. Instead callback guard and callback function are combined into a single CallbackData struct, while primary data lock is stored separately.
* CallbackData member of class FlagImpl is initially set to be nullptr and is only allocated and initialized when a flag's callback is being set. For most flags we do not pay for the extra space and extra absl::Mutex now.
* Primary data guard is stored in data_guard_ data member. This is a properly aligned character buffer of necessary size. During initialization of the flag we construct absl::Mutex in this space using placement new call.
* We now avoid extra value copy after successful attempt to parse value out of string. Instead we swap flag's current value with tentative value we just produced.

PiperOrigin-RevId: 285132636

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ed45d118fb818969eb13094cf7827c885dfc562c by Tom Manshreck <shreck@google.com>:

Change null-term* (and nul-term*) to NUL-term* in comments

PiperOrigin-RevId: 285036610

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729619017944db895ce8d6d29c1995aa2e5628a5 by Derek Mauro <dmauro@google.com>:

Use the Posix implementation of thread identity on MinGW.
Some versions of MinGW suffer from thread_local bugs.

PiperOrigin-RevId: 285022920

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39a25493503c76885bc3254c28f66a251c5b5bb0 by Greg Falcon <gfalcon@google.com>:

Implementation detail change.

Add further ABSL_NAMESPACE_BEGIN and _END annotation macros to files in Abseil.

PiperOrigin-RevId: 285012012
GitOrigin-RevId: c99f979ad34f155fbeeea69b88bdc7458d89a21c
Change-Id: I4c85d3704e45d11a9ac50d562f39640a6adbedc1
2019-12-12 15:37:13 -05:00

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed 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
//
// https://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.
//
// -----------------------------------------------------------------------------
// File: declare.h
// -----------------------------------------------------------------------------
//
// This file defines the ABSL_DECLARE_FLAG macro, allowing you to declare an
// `absl::Flag` for use within a translation unit. You should place this
// declaration within the header file associated with the .cc file that defines
// and owns the `Flag`.
#ifndef ABSL_FLAGS_DECLARE_H_
#define ABSL_FLAGS_DECLARE_H_
#include "absl/strings/string_view.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
// absl::Flag<T> represents a flag of type 'T' created by ABSL_FLAG.
template <typename T>
class Flag;
} // namespace flags_internal
// Flag
//
// Forward declaration of the `absl::Flag` type for use in defining the macro.
#if defined(_MSC_VER) && !defined(__clang__)
template <typename T>
class Flag;
#else
template <typename T>
using Flag = flags_internal::Flag<T>;
#endif
ABSL_NAMESPACE_END
} // namespace absl
// ABSL_DECLARE_FLAG()
//
// This macro is a convenience for declaring use of an `absl::Flag` within a
// translation unit. This macro should be used within a header file to
// declare usage of the flag within any .cc file including that header file.
//
// The ABSL_DECLARE_FLAG(type, name) macro expands to:
//
// extern absl::Flag<type> FLAGS_name;
#define ABSL_DECLARE_FLAG(type, name) extern ::absl::Flag<type> FLAGS_##name
#endif // ABSL_FLAGS_DECLARE_H_