Files
abseil-cpp/absl/base/internal/sysinfo.h
Abseil Team 2c8a5b0d89 Export of internal Abseil changes
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873b52b0a691e759413c5db27dafc541a5da5263 by Andy Getzendanner <durandal@google.com>:

Introduce an internal-only thread-local caching wrapper around GetTID.

PiperOrigin-RevId: 323055682

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091a4537f1ef6e158acbf4261cfae1af7a3bdb7f by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 322864497

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c80ccfff2a825819f31826a30f48cca3297699f8 by Evan Brown <ezb@google.com>:

Roll forward b-tree changes simplifying deletion and getting rid of recursion in clear_and_delete().

We also change clear_and_delete() to avoid some unnecessary comparisons by restructuring the loops.

PiperOrigin-RevId: 322658938

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81464c0fb9c8c6268dca2e530aba99e75e1e59ae by Gennadiy Rozental <rogeeff@google.com>:

Eliminate definition of RunningOnValgrind inside the library.

Fixes #674
Fixes #657

PiperOrigin-RevId: 322508440
GitOrigin-RevId: 873b52b0a691e759413c5db27dafc541a5da5263
Change-Id: I20b40c9e8fc62edcf981caab467cca33cf6fd2ba
2020-07-24 16:15:46 -04:00

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2.6 KiB
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// Copyright 2017 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.
//
// This file includes routines to find out characteristics
// of the machine a program is running on. It is undoubtedly
// system-dependent.
// Functions listed here that accept a pid_t as an argument act on the
// current process if the pid_t argument is 0
// All functions here are thread-hostile due to file caching unless
// commented otherwise.
#ifndef ABSL_BASE_INTERNAL_SYSINFO_H_
#define ABSL_BASE_INTERNAL_SYSINFO_H_
#ifndef _WIN32
#include <sys/types.h>
#endif
#include <cstdint>
#include "absl/base/config.h"
#include "absl/base/port.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
// Nominal core processor cycles per second of each processor. This is _not_
// necessarily the frequency of the CycleClock counter (see cycleclock.h)
// Thread-safe.
double NominalCPUFrequency();
// Number of logical processors (hyperthreads) in system. Thread-safe.
int NumCPUs();
// Return the thread id of the current thread, as told by the system.
// No two currently-live threads implemented by the OS shall have the same ID.
// Thread ids of exited threads may be reused. Multiple user-level threads
// may have the same thread ID if multiplexed on the same OS thread.
//
// On Linux, you may send a signal to the resulting ID with kill(). However,
// it is recommended for portability that you use pthread_kill() instead.
#ifdef _WIN32
// On Windows, process id and thread id are of the same type according to the
// return types of GetProcessId() and GetThreadId() are both DWORD, an unsigned
// 32-bit type.
using pid_t = uint32_t;
#endif
pid_t GetTID();
// Like GetTID(), but caches the result in thread-local storage in order
// to avoid unnecessary system calls. Note that there are some cases where
// one must call through to GetTID directly, which is why this exists as a
// separate function. For example, GetCachedTID() is not safe to call in
// an asynchronous signal-handling context nor right after a call to fork().
pid_t GetCachedTID();
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_BASE_INTERNAL_SYSINFO_H_