This introduces a new internal utility, std::__condvar, which is a
simplified form of std::condition_variable. It has no dependency on
<chrono> or std::unique_lock, which allows it to be used in
<bits/atomic_wait.h>.
This avoids repeating the #ifdef __GTHREAD_COND_INIT preprocessor
conditions and associated logic for initializing a __gthread_cond_t
correctly. It also encapsulates most of the __gthread_cond_xxx functions
as member functions of __condvar.
libstdc++-v3/ChangeLog:
* include/bits/atomic_timed_wait.h (__cond_wait_until_impl):
Do not define when _GLIBCXX_HAVE_LINUX_FUTEX is defined. Use
__condvar and mutex instead of __gthread_cond_t and
unique_lock<mutex>.
(__cond_wait_until): Likewise. Fix test for return value of
__cond_wait_until_impl.
(__timed_waiters::_M_do_wait_until): Use __condvar instead
of __gthread_cond_t.
* include/bits/atomic_wait.h: Remove <bits/unique_lock.h>
include. Only include <bits/std_mutex.h> if not using futexes.
(__platform_wait_max_value): Remove unused variable.
(__waiters::lock_t): Use lock_guard instead of unique_lock.
(__waiters::_M_cv): Use __condvar instead of __gthread_cond_t.
(__waiters::_M_do_wait(__platform_wait_t)): Likewise.
(__waiters::_M_notify()): Likewise. Use notify_one() if not
asked to notify all.
* include/bits/std_mutex.h (__condvar): New type.
* include/std/condition_variable (condition_variable::_M_cond)
(condition_variable::wait_until): Use __condvar instead of
__gthread_cond_t.
* src/c++11/condition_variable.cc (condition_variable): Define
default constructor and destructor as defaulted.
(condition_variable::wait, condition_variable::notify_one)
(condition_variable::notify_all): Forward to corresponding
member function of __condvar.
By moving std::make_obj_using_allocator and the related "utility
functions for uses-allocator construction" to a new header, we can avoid
including the whole of <memory> in <scoped_allocator> and
<memory_resource>.
In order to simplify the implementation of those utility functions they
now use concepts unconditionally. They are no longer defined if
__cpp_concepts is not defined. To simplify the code that uses those
functions I've introduced a __cpp_lib_make_obj_using_allocator feature
test macro (not specified in the standard, which might be an oversight).
That allows the code in <memory_resource> and <scoped_allocator> to
check the feature test macro to decide whether to use the new utilities,
or fall back to the C++17 code.
At the same time, this reshuffles some of the headers included by
<memory> so that they are (mostly?) self-contained. It should no longer
be necessary to include other headers before <bits/shared_ptr.h> when
other parts of the library want to use std::shared_ptr without including
the whole of <memory>.
libstdc++-v3/ChangeLog:
* include/Makefile.am: Add new header.
* include/Makefile.in: Regenerate.
* include/bits/shared_ptr.h: Include <iosfwd>.
* include/bits/shared_ptr_base.h: Include required headers here
directly, instead of in <memory>.
* include/bits/uses_allocator_args.h: New file. Move utility
functions for uses-allocator construction from <memory> to here.
Only define the utility functions when concepts are available.
(__cpp_lib_make_obj_using_allocator): Define non-standard
feature test macro.
* include/std/condition_variable: Remove unused headers.
* include/std/future: Likewise.
* include/std/memory: Remove headers that are not needed
directly, and are now inclkuded where they're needed. Include
new <bits/uses_allocator_args.h> header.
* include/std/memory_resource: Include only the necessary
headers. Use new feature test macro to detect support for the
utility functions.
* include/std/scoped_allocator: Likewise.
* include/std/version (__cpp_lib_make_obj_using_allocator):
Define.
The fix for PR68519 in 83fd5e73b3 only
applied to condition_variable::wait_for. This problem can also apply to
condition_variable::wait_until but only if the custom clock is using a
more recent epoch so that a small enough delta can be calculated. let's
use the newly-added chrono::__detail::ceil to fix this and also make use
of that function to simplify the previous wait_for fixes.
Also, simplify the existing test case for PR68519 a little and make its
variables local so we can add a new test case for the above problem.
Unfortunately, the test would have only started failing if sufficient
time has passed since the chrono::steady_clock epoch had passed anyway,
but it's better than nothing.
libstdc++-v3/ChangeLog:
* include/std/condition_variable (condition_variable::wait_until):
Convert delta to steady_clock duration before adding to current
steady_clock time to avoid rounding errors described in PR68519.
(condition_variable::wait_for): Simplify calculation of absolute
time by using chrono::__detail::ceil in both overloads.
* testsuite/30_threads/condition_variable/members/68519.cc:
(test_wait_for): Renamed from test01. Replace unassigned val
variable with constant false. Reduce scope of mx and cv
variables to just test_wait_for function.
(test_wait_until): Add new test case.
libstdc++-v3/ChangeLog:
* include/experimental/bits/shared_ptr.h (shared_ptr(auto_ptr&&))
(operator=(auto_ptr&&)): Add diagnostic pragmas to suppress
warnings for uses of std::auto_ptr.
* include/experimental/type_traits (is_literal_type_v):
Likewise, for use of std::is_literal_type.
* include/std/condition_variable (condition_variable_any::_Unlock):
Likewise, for use of std::uncaught_exception.
For C++20 the wait_until members of mutexes and condition variables are
required to be ill-formed if given a clock that doesn't meet the
requirements for a clock type. To implement that requirement this patch
adds static assertions using the chrono::is_clock trait, and defines
that trait.
To avoid expensive checks for the common cases, the trait (and
associated variable template) are explicitly specialized for the
standard clock types.
This also moves the filesystem::__file_clock type from <filesystem> to
<chrono>, so that chrono::file_clock and chrono::file_time can be
defined in <chrono> as required.
* include/bits/fs_fwd.h (filesystem::__file_clock): Move to ...
* include/std/chrono (filesystem::__file_clock): Here.
(filesystem::__file_clock::from_sys, filesystem::__file_clock::to_sys):
Define public member functions for C++20.
(is_clock, is_clock_v): Define traits for C++20.
* include/std/condition_variable (condition_variable::wait_until): Add
check for valid clock.
* include/std/future (_State_baseV2::wait_until): Likewise.
* include/std/mutex (__timed_mutex_impl::_M_try_lock_until): Likewise.
* include/std/shared_mutex (shared_timed_mutex::try_lock_shared_until):
Likewise.
* include/std/thread (this_thread::sleep_until): Likewise.
* testsuite/30_threads/condition_variable/members/2.cc: Qualify
slow_clock with new namespace.
* testsuite/30_threads/condition_variable/members/clock_neg.cc: New
test.
* testsuite/30_threads/condition_variable_any/members/clock_neg.cc:
New test.
* testsuite/30_threads/future/members/clock_neg.cc: New test.
* testsuite/30_threads/recursive_timed_mutex/try_lock_until/3.cc:
Qualify slow_clock with new namespace.
* testsuite/30_threads/recursive_timed_mutex/try_lock_until/
clock_neg.cc: New test.
* testsuite/30_threads/shared_future/members/clock_neg.cc: New
test.
* testsuite/30_threads/shared_lock/locking/clock_neg.cc: New test.
* testsuite/30_threads/shared_timed_mutex/try_lock_until/clock_neg.cc:
New test.
* testsuite/30_threads/timed_mutex/try_lock_until/3.cc: Qualify
slow_clock with new namespace.
* testsuite/30_threads/timed_mutex/try_lock_until/4.cc: Likewise.
* testsuite/30_threads/timed_mutex/try_lock_until/clock_neg.cc: New
test.
* testsuite/30_threads/unique_lock/locking/clock_neg.cc: New test.
* testsuite/std/time/traits/is_clock.cc: New test.
* testsuite/util/slow_clock.h (slow_clock): Move to __gnu_test
namespace.
2020-01-07 Thomas Rodgers <trodgers@redhat.com>
* include/std/condition_variable
(condition_variable_any::wait_on): Rename to match current draft
standard.
(condition_variable_any::wait_on_until): Likewise.
(condition_variable_any::wait_on_for): Likewise.
* testsuite/30_threads/condition_variable_any/stop_token/wait_on.cc:
Adjust tests to account for renamed methods.
From-SVN: r279988
* include/Makefile.am: Add <stop_token> header.
* include/Makefile.in: Regenerate.
* include/std/condition_variable: Add overloads for stop_token support
to condition_variable_any.
* include/std/stop_token: New file.
* include/std/thread: Add jthread type.
* include/std/version (__cpp_lib_jthread): New value.
* testsuite/30_threads/condition_variable_any/stop_token/1.cc: New test.
* testsuite/30_threads/condition_variable_any/stop_token/2.cc: New test.
* testsuite/30_threads/condition_variable_any/stop_token/wait_on.cc: New test.
* testsuite/30_threads/jthread/1.cc: New test.
* testsuite/30_threads/jthread/2.cc: New test.
* testsuite/30_threads/jthread/jthread.cc: New test.
* testsuite/30_threads/stop_token/1.cc: New test.
* testsuite/30_threads/stop_token/2.cc: New test.
* testsuite/30_threads/stop_token/stop_token.cc: New test.
From-SVN: r278274
The pthread_cond_clockwait function is available in glibc since the 2.30
release. If this function is available in the C library it can be used
to fix PR libstdc++/41861 by supporting std::chrono::steady_clock
properly with std::condition_variable.
This means that code using std::condition_variable::wait_for or
std::condition_variable::wait_until with std::chrono::steady_clock is no
longer subject to timing out early or potentially waiting for much
longer if the system clock is warped at an inopportune moment.
If pthread_cond_clockwait is available then std::chrono::steady_clock is
deemed to be the "best" clock available which means that it is used for
the relative wait_for calls and absolute wait_until calls using
user-defined clocks. Calls explicitly using std::chrono::system_clock
continue to use CLOCK_REALTIME via __gthread_cond_timedwait.
If pthread_cond_clockwait is not available then
std::chrono::system_clock is deemed to be the "best" clock available
which means that the previous suboptimal behaviour remains.
2019-09-04 Mike Crowe <mac@mcrowe.com>
PR libstdc++/41861
* acinclude.m4 (GLIBCXX_CHECK_PTHREAD_COND_CLOCKWAIT): Check for new
pthread_cond_clockwait function.
* configure.ac: Use GLIBCXX_CHECK_PTHREAD_COND_CLOCKWAIT.
* configure: Regenerate.
* config.h.in: Regenerate.
* include/std/condition_variable: (condition_variable): Rename
__steady_clock_t typedef and add system_clock. Change __clock_t to be
a typedef for the preferred clock to convert arbitrary other clocks to.
[_GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT] (wait_until): Add a steady_clock
overload.
(wait_until): Change __clock_t overload to use system_clock.
[_GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT] (__wait_until_impl): Add
steady_clock overload that calls pthread_cond_clockwait.
(__wait_until_impl): Change __clock_t overload to use system_clock.
(condition_variable_any) [_GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT]: Use
steady_clock for __clock_t if pthread_cond_clockwait is available.
From-SVN: r275390
In r263225 (d2e378182a12d68fe5caeffae681252662a2fe7b), I fixed
condition_variable::wait_for to use std::chrono::steady_clock for the wait.
Unfortunately, I failed to spot that the same fix is required for the
wait_for variant that takes a predicate too.
2018-09-25 Mike Crowe <mac@mcrowe.com>
* include/std/condition_variable (condition_variable::wait_for): Use
steady clock in overload that uses a predicate.
From-SVN: r264575
The C++ standard says that std::condition_variable::wait_for should be
implemented to be equivalent to:
return wait_until(lock, chrono::steady_clock::now() + rel_time);
But the existing implementation uses chrono::system_clock. Now that
wait_until has potentially-different behaviour for chrono::steady_clock,
let's at least try to wait using the correct clock.
2018-08-01 Mike Crowe <mac@mcrowe.com>
* include/std/condition_variable (wait_for): Use steady_clock.
From-SVN: r263225
As currently implemented, condition_variable always ultimately waits
against std::chrono::system_clock. This clock can be changed in arbitrary
ways by the user which may result in us waking up too early or too late
when measured against the caller-supplied clock.
We can't (yet) do much about waking up too late (PR 41861), but
if we wake up too early we must return cv_status::no_timeout to indicate a
spurious wakeup rather than incorrectly returning cv_status::timeout.
2018-08-01 Mike Crowe <mac@mcrowe.com>
* include/std/condition_variable (wait_until): Only report timeout
if we really have timed out when measured against the
caller-supplied clock.
* testsuite/30_threads/condition_variable/members/2.cc: Add test
case to confirm above behaviour.
From-SVN: r263224
This will allow std::mutex and std::lock_guard to be used elsewhere in
the library without pulling in the whole of <chrono>.
Previously the whole of <bits/std_mutex.h> was conditional on the
_GLIBCXX_USE_C99_STDINT_TR1 macro, but only the std::unique_lock members
that use <chrono> facilities should depend on that. std::mutex only
needs to depend on _GLIBCXX_HAS_GTHREADS and std::lock_guard can be
defined unconditionally.
Some parts of <bits/std_mutex.h> and <mutex> are based on code in
<ext/concurrence.h> which dates from 2003. However, the std::unique_lock
implementation was added in 2008 by r135007, without using any earlier
code. Therefore the new header file has copyright years 2008-2018.
* include/Makefile.am: Add new <bits/unique_lock.h> header.
* include/Makefile.in: Regenerate.
* include/bits/std_mutex.h [!_GLIBCXX_USE_C99_STDINT_TR1] (mutex)
(lock_guard): Define independent of _GLIBCXX_USE_C99_STDINT_TR1.
(unique_lock): Move definition to ...
* include/bits/unique_lock.h: New header.
[!_GLIBCXX_USE_C99_STDINT_TR1] (unique_lock): Define unconditionally.
[_GLIBCXX_USE_C99_STDINT_TR1] (unique_lock(mutex_type&, time_point))
(unique_lock(mutex_type&, duration), unique_lock::try_lock_until)
(unique_lock::try_lock_for): Define only when <chrono> is usable.
* include/std/condition_variable: Include <bits/unique_lock.h>.
* include/std/mutex: Likewise.
From-SVN: r262963
* config/abi/pre/gnu.ver: Add new exports.
* include/std/condition_variable (notify_all_at_thread_exit): Declare.
(__at_thread_exit_elt): New base class.
* include/std/future: Add comments documenting the implementation.
(__future_base::_State_baseV2::_State_baseV2()): Use brace-or-equal
initializers and define constructor as defaulted.
(__future_base::_State_baseV2::_M_ready): Replace member function
with member variable.
(__future_base::_State_baseV2::_M_set_result): Set _M_ready.
(__future_base::_State_baseV2::_M_set_delayed_result): Define.
(__future_base::_State_baseV2::_M_break_promise): Set _M_ready.
(__future_base::_State_baseV2::_Make_ready): New helper class.
(__future_base::_Deferred_state::_M_has_deferred): Remove requirement
for caller to own mutex.
(__future_base::_Async_state_impl::~_Async_state_impl): Call join
directly.
(__future_base::_Task_state_base::_M_run): Take arguments by
reference.
(__future_base::_Task_state_base::_M_run_delayed): Declare new pure
virtual function.
(__future_base::_Task_state::_M_run_delayed): Define override.
(promise::set_value_at_thread_exit): Define.
(promise::set_exception_at_thread_exit): Define.
(packaged_task::make_ready_at_thread_exit): Define.
* src/c++11/condition_variable.cc (notify_all_at_thread_exit): Define.
* src/c++11/future.cc
(__future_base::_State_baseV2::_Make_ready::_M_set): Define.
* testsuite/30_threads/condition_variable/members/3.cc: New.
* testsuite/30_threads/packaged_task/members/at_thread_exit.cc: New.
* testsuite/30_threads/promise/members/at_thread_exit.cc: New.
From-SVN: r218255
PR libstdc++/53830
* include/std/condition_variable (condition_variable_any::wait):
Move _Unlock type to class scope.
(condition_variable_any::wait_until): Reuse it.
* testsuite/30_threads/condition_variable_any/53830.cc: New.
From-SVN: r189268
PR libstdc++/50862
* include/std/condition_variable (condition_variable_any::wait): Fix
deadlock and ensure _Lock::lock() is called on exit.
(condition_variable_any::native_handle): Remove, as per LWG 1500.
* testsuite/30_threads/condition_variable_any/50862.cc: New.
From-SVN: r180446
PR libstdc++/49894
* include/std/mutex (__mutex_base,__recursive_mutex_base): Define new
base classes to manage construction/destruction of native mutexes,
using NSDMI when INIT macros are defined.
(mutex,recursive_mutex,timed_mutex,recursive_timed_mutex): Derive from
new base classes.
* include/std/condition_variable (condition_variable): Use NSDMI when
INIT macro is defined. Use noexcept.
* src/condition_variable.cc (condition_variable): Explicitly-default
constructor/destructor when using NSDMI. Use noexcept.
(condition_variable_any): Likewise.
From-SVN: r180411
2010-11-18 Benjamin Kosnik <bkoz@redhat.com>
* config/*/*: Use headername alias to associate private includes
to public includes.
* include/*/*: Same.
* scripts/run_doxygen: Update for doxygen 1.7.2.
* doc/doxygen/user.cfg.in: Same.
* doc/doxygen/TODO: Remove.
* testsuite/*/std_c++0x_neg.cc: Adjust line number.
From-SVN: r168046
2010-01-31 Paolo Carlini <paolo.carlini@oracle.com>
Revert last changes. Also revert, among the previous changes:
* include/std/condition_variable (condition_variable_any::
wait<>(_Lock&)): Provide definition.
From-SVN: r156403
