4896bb3199
The std:🧵:id formatter uses std::basic_ostringstream without including <sstream>, which went unnoticed because the test for it uses a stringstream to check the output is correct. The fix implemented here is to stop using basic_ostringstream for formatting thread::id and just use std::format instead. As a drive-by fix, the formatter specialization is constrained to require that the thread:🆔:native_handle_type can be formatted, to avoid making the formatter ill-formed if the pthread_t type is not a pointer or integer. Since non-void pointers can't be formatted, ensure that we convert pointers to const void* for formatting. Make a similar change to the existing operator<< overload so that in the unlikely case that pthread_t is a typedef for char* we don't treat it as a null-terminated string when inserting into a stream. libstdc++-v3/ChangeLog: PR libstdc++/115099 * include/bits/std_thread.h: Declare formatter as friend of thread::id. * include/std/thread (operator<<): Convert non-void pointers to void pointers for output. (formatter): Add constraint that thread::native_handle_type is a pointer or integer. (formatter::format): Reimplement without basic_ostringstream. * testsuite/30_threads/thread/id/output.cc: Check output compiles before <sstream> has been included. (cherry picked from commit 1a5e4dd83788ea4c049d354d83ad58a6a3d747e6)
387 lines
10 KiB
C++
387 lines
10 KiB
C++
// std::thread declarations -*- C++ -*-
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// Copyright (C) 2008-2024 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file bits/std_thread.h
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* This is an internal header file, included by other library headers.
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* Do not attempt to use it directly. @headername{thread}
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*/
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#ifndef _GLIBCXX_THREAD_H
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#define _GLIBCXX_THREAD_H 1
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#pragma GCC system_header
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#if __cplusplus >= 201103L
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#include <bits/c++config.h>
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#include <iosfwd> // std::basic_ostream
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#include <tuple> // std::tuple
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#include <bits/functional_hash.h> // std::hash
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#include <bits/invoke.h> // std::__invoke
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#include <bits/refwrap.h> // not required, but helpful to users
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#include <bits/unique_ptr.h> // std::unique_ptr
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#ifdef _GLIBCXX_HAS_GTHREADS
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# include <bits/gthr.h>
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#else
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# include <errno.h>
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# include <bits/functexcept.h>
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#endif
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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#if __glibcxx_formatters
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template<typename, typename> class formatter;
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#endif
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/** @addtogroup threads
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* @{
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*/
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/** A std::thread represents a new thread of execution.
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*
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* The default constructor creates an object that does not own a thread.
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* The `thread(F&&, Args&&...)` constructor invokes a callable in a new
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* thread, and owns that new thread. A `std::thread` that owns a thread
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* is *joinable*. Joining a thread waits for it to finish executing,
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* which happens when the callable running in that thread returns.
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*
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* A `std::thread` cannot be copied, but can be moved. Moving a joinable
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* object transfers ownership of its thread to another object.
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*
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* A joinable `std::thread` must be explicitly joined (or detached) before
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* it is destroyed or assigned to. Attempting to destroy a joinable thread
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* will terminate the whole process.
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*
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* @headerfile thread
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* @since C++11
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*/
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class thread
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{
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public:
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#ifdef _GLIBCXX_HAS_GTHREADS
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using native_handle_type = __gthread_t;
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#else
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using native_handle_type = int;
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#endif
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/** A std::thread::id is a unique identifier for a thread.
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*
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* @headerfile thread
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* @since C++11
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*/
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class id
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{
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native_handle_type _M_thread;
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public:
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id() noexcept : _M_thread() { }
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explicit
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id(native_handle_type __id) : _M_thread(__id) { }
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private:
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friend class thread;
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friend struct hash<id>;
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friend bool
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operator==(id __x, id __y) noexcept;
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#if __cpp_lib_three_way_comparison
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friend strong_ordering
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operator<=>(id __x, id __y) noexcept;
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#else
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friend bool
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operator<(id __x, id __y) noexcept;
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#endif
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template<class _CharT, class _Traits>
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friend basic_ostream<_CharT, _Traits>&
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operator<<(basic_ostream<_CharT, _Traits>& __out, id __id);
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#if __glibcxx_formatters
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friend formatter<id, char>;
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friend formatter<id, wchar_t>;
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#endif
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};
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private:
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id _M_id;
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// 2097. packaged_task constructors should be constrained
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// 3039. Unnecessary decay in thread and packaged_task
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template<typename _Tp>
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using __not_same = __not_<is_same<__remove_cvref_t<_Tp>, thread>>;
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public:
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thread() noexcept = default;
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#ifdef _GLIBCXX_HAS_GTHREADS
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private:
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// This adds to user code that creates std:thread objects (because
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// it is called by the template ctor below) strong references to
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// pthread_create and pthread_join, which ensures they are both
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// linked in even during static linking. We can't depend on
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// gthread calls to bring them in, because those may use weak
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// references.
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static void
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_M_thread_deps_never_run() {
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#ifdef GTHR_ACTIVE_PROXY
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reinterpret_cast<void (*)(void)>(&pthread_create)();
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reinterpret_cast<void (*)(void)>(&pthread_join)();
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#endif
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}
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public:
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template<typename _Callable, typename... _Args,
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typename = _Require<__not_same<_Callable>>>
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explicit
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thread(_Callable&& __f, _Args&&... __args)
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{
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static_assert( __is_invocable<typename decay<_Callable>::type,
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typename decay<_Args>::type...>::value,
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"std::thread arguments must be invocable after conversion to rvalues"
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);
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using _Wrapper = _Call_wrapper<_Callable, _Args...>;
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// Create a call wrapper with DECAY_COPY(__f) as its target object
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// and DECAY_COPY(__args)... as its bound argument entities.
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_M_start_thread(_State_ptr(new _State_impl<_Wrapper>(
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std::forward<_Callable>(__f), std::forward<_Args>(__args)...)),
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_M_thread_deps_never_run);
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}
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#endif // _GLIBCXX_HAS_GTHREADS
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~thread()
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{
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if (joinable())
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std::__terminate();
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}
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thread(const thread&) = delete;
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thread(thread&& __t) noexcept
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{ swap(__t); }
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thread& operator=(const thread&) = delete;
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thread& operator=(thread&& __t) noexcept
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{
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if (joinable())
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std::__terminate();
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swap(__t);
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return *this;
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}
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void
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swap(thread& __t) noexcept
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{ std::swap(_M_id, __t._M_id); }
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bool
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joinable() const noexcept
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{ return !(_M_id == id()); }
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void
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join();
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void
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detach();
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id
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get_id() const noexcept
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{ return _M_id; }
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/** @pre thread is joinable
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*/
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native_handle_type
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native_handle()
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{ return _M_id._M_thread; }
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// Returns a value that hints at the number of hardware thread contexts.
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static unsigned int
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hardware_concurrency() noexcept;
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#ifdef _GLIBCXX_HAS_GTHREADS
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#ifndef _GLIBCXX_THREAD_IMPL
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private:
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#endif
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// Abstract base class for types that wrap arbitrary functors to be
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// invoked in the new thread of execution.
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struct _State
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{
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virtual ~_State();
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virtual void _M_run() = 0;
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};
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using _State_ptr = unique_ptr<_State>;
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private:
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template<typename _Callable>
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struct _State_impl : public _State
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{
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_Callable _M_func;
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template<typename... _Args>
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_State_impl(_Args&&... __args)
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: _M_func(std::forward<_Args>(__args)...)
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{ }
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void
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_M_run() { _M_func(); }
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};
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void
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_M_start_thread(_State_ptr, void (*)());
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#if _GLIBCXX_THREAD_ABI_COMPAT
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public:
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struct _Impl_base;
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typedef shared_ptr<_Impl_base> __shared_base_type;
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struct _Impl_base
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{
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__shared_base_type _M_this_ptr;
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virtual ~_Impl_base() = default;
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virtual void _M_run() = 0;
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};
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private:
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void
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_M_start_thread(__shared_base_type, void (*)());
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void
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_M_start_thread(__shared_base_type);
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#endif
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private:
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// A call wrapper that does INVOKE(forwarded tuple elements...)
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template<typename _Tuple>
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struct _Invoker
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{
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template<typename... _Args>
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explicit
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_Invoker(_Args&&... __args)
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: _M_t(std::forward<_Args>(__args)...)
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{ }
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_Tuple _M_t;
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template<typename>
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struct __result;
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template<typename _Fn, typename... _Args>
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struct __result<tuple<_Fn, _Args...>>
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: __invoke_result<_Fn, _Args...>
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{ };
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template<size_t... _Ind>
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typename __result<_Tuple>::type
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_M_invoke(_Index_tuple<_Ind...>)
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{ return std::__invoke(std::get<_Ind>(std::move(_M_t))...); }
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typename __result<_Tuple>::type
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operator()()
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{
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using _Indices
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= typename _Build_index_tuple<tuple_size<_Tuple>::value>::__type;
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return _M_invoke(_Indices());
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}
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};
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public:
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/// @cond undocumented
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template<typename... _Tp>
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using _Call_wrapper = _Invoker<tuple<typename decay<_Tp>::type...>>;
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/// @endcond
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#endif // _GLIBCXX_HAS_GTHREADS
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};
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#ifndef _GLIBCXX_HAS_GTHREADS
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inline void thread::join() { std::__throw_system_error(EINVAL); }
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inline void thread::detach() { std::__throw_system_error(EINVAL); }
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inline unsigned int thread::hardware_concurrency() noexcept { return 0; }
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#endif
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/// @relates std::thread
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inline void
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swap(thread& __x, thread& __y) noexcept
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{ __x.swap(__y); }
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/// @relates std::thread::id
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inline bool
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operator==(thread::id __x, thread::id __y) noexcept
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{
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// pthread_equal is undefined if either thread ID is not valid, so we
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// can't safely use __gthread_equal on default-constructed values (nor
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// the non-zero value returned by this_thread::get_id() for
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// single-threaded programs using GNU libc). Assume EqualityComparable.
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return __x._M_thread == __y._M_thread;
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}
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// N.B. other comparison operators are defined in <thread>
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// DR 889.
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/// std::hash specialization for thread::id.
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template<>
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struct hash<thread::id>
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: public __hash_base<size_t, thread::id>
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{
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size_t
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operator()(const thread::id& __id) const noexcept
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{ return std::_Hash_impl::hash(__id._M_thread); }
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};
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namespace this_thread
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{
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/// The unique identifier of the current thread.
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inline thread::id
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get_id() noexcept
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{
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#ifndef _GLIBCXX_HAS_GTHREADS
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return thread::id(1);
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#elif defined _GLIBCXX_NATIVE_THREAD_ID
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return thread::id(_GLIBCXX_NATIVE_THREAD_ID);
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#else
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return thread::id(__gthread_self());
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#endif
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}
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/// Allow the implementation to schedule a different thread.
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inline void
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yield() noexcept
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{
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#if defined _GLIBCXX_HAS_GTHREADS && defined _GLIBCXX_USE_SCHED_YIELD
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__gthread_yield();
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#endif
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}
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} // namespace this_thread
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/// @}
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace
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#endif // C++11
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#endif // _GLIBCXX_THREAD_H
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