This makes the hash function available without including the whole of
<thread>, which is needed for <barrier>.
libstdc++-v3/ChangeLog:
* include/bits/std_thread.h (hash<thread::id>): Move here,
from ...
* include/std/thread (hash<thread::id>): ... here.
In previous releases the std::this_thread::sleep_for function was only
declared if the target supports multiple threads. I changed that
recently in r11-2649-g5bbb1f3000c57fd4d95969b30fa0e35be6d54ffb so that
sleep_for could be used single-threaded. But that means that targets
using --disable-threads are now required to provide some way to sleep.
This breaks the build for (at least) AVR when trying to build a hosted
library.
This patch adds a new autoconf macro that is defined when no way to
sleep is available, and uses that to suppress the sleeping functions in
std::this_thread.
The #error in src/c++11/thread.cc is retained for the case where there
is no sleep function available but multiple threads are supported. This
is consistent with previous releases, but that #error could probably be
removed without any consequences.
libstdc++-v3/ChangeLog:
* acinclude.m4 (GLIBCXX_ENABLE_LIBSTDCXX_TIME): Define NO_SLEEP
if none of nanosleep, sleep and Sleep is available.
* config.h.in: Regenerate.
* configure: Regenerate.
* include/std/thread [_GLIBCXX_NO_SLEEP] (__sleep_for): Do
not declare.
[_GLIBCXX_NO_SLEEP] (sleep_for, sleep_until): Do not
define.
* src/c++11/thread.cc [_GLIBCXX_NO_SLEEP] (__sleep_for): Do
not define.
This makes it possible to use std::thread without including the whole of
<thread>. It also makes this_thread::get_id() and this_thread::yield()
available even when there is no gthreads support (e.g. when GCC is built
with --disable-threads or --enable-threads=single).
In order for the std:🧵:id return type of this_thread::get_id() to
be defined, std:thread itself is defined unconditionally. However the
constructor that creates new threads is not defined for single-threaded
builds. The thread::join() and thread::detach() member functions are
defined inline for single-threaded builds and just throw an exception
(because we know the thread cannot be joinable if the constructor that
creates joinable threads doesn't exit).
The thread::hardware_concurrency() member function is also defined
inline and returns 0 (as suggested by the standard when the value "is
not computable or well-defined").
The main benefit for most targets is that other headers such as <future>
do not need to include the whole of <thread> just to be able to create a
std::thread. That avoids including <stop_token> and std::jthread where
not required. This is another partial fix for PR 92546.
This also means we can use this_thread::get_id() and this_thread::yield()
in <stop_token> instead of using the gthread functions directly. This
removes some preprocessor conditionals, simplifying the code.
libstdc++-v3/ChangeLog:
PR libstdc++/92546
* include/Makefile.am: Add new <bits/std_thread.h> header.
* include/Makefile.in: Regenerate.
* include/std/future: Include new header instead of <thread>.
* include/std/stop_token: Include new header instead of
<bits/gthr.h>.
(stop_token::_S_yield()): Use this_thread::yield().
(_Stop_state_t::_M_requester): Change type to std:🧵:id.
(_Stop_state_t::_M_request_stop()): Use this_thread::get_id().
(_Stop_state_t::_M_remove_callback(_Stop_cb*)): Likewise.
Use __is_single_threaded() to decide whether to synchronize.
* include/std/thread (thread, operator==, this_thread::get_id)
(this_thread::yield): Move to new header.
(operator<=>, operator!=, operator<, operator<=, operator>)
(operator>=, hash<thread::id>, operator<<): Define even when
gthreads not available.
* src/c++11/thread.cc: Include <memory>.
* include/bits/std_thread.h: New file.
(thread, operator==, this_thread::get_id, this_thread::yield):
Define even when gthreads not available.
[!_GLIBCXX_HAS_GTHREADS] (thread::join, thread::detach)
(thread::hardware_concurrency): Define inline.
Move assigning to a std::jthread that represents a thread of execution
needs to send a stop request and join that running thread. Otherwise the
std::thread data member will terminate in its assignment operator.
Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/std/thread (jthread::operator=(jthread&&)): Transfer
any existing state to a temporary that will request a stop and
then join.
* testsuite/30_threads/jthread/jthread.cc: Test move assignment.
As was previously done for std::thread, this removes an unnecessary copy
of an rvalue of type thread::_Invoker. Instead of creating the rvalue
and then moving that into the shared state, the member of the shared
state is initialized directly from the forwarded callable and bound
arguments.
This also slightly simplifies std::thread creation to remove the
_S_make_state helper function.
libstdc++-v3/ChangeLog:
PR libstdc++/69724
* include/std/future (__future_base::_S_make_deferred_state)
(__future_base::_S_make_async_state): Remove.
(__future_base::_Deferred_state): Change constructor to accept a
parameter pack of arguments and forward them to the call
wrapper.
(__future_base::_Async_state_impl): Likewise. Replace lambda
expression with a named member function.
(async): Construct state object directly from the arguments,
instead of using thread::__make_invoker, _S_make_deferred_state
and _S_make_async_state. Move shared state into the returned
future.
* include/std/thread (thread::_Call_wrapper): New alias
template for use by constructor and std::async.
(thread::thread(Callable&&, Args&&...)): Create state object
directly instead of using _S_make_state.
(thread::__make_invoker, thread::__decayed_tuple)
(thread::_S_make_state): Remove.
* testsuite/30_threads/async/69724.cc: New test.
The only function in namespace std::this_thread that actually depends on
thread support being present is this_thread::get_id(). The other
functions (yield, sleep_for and sleep_until) can be defined for targets
without gthreads.
A small change is needed in std::this_thread::sleep_for which currently
uses the __gthread_time_t typedef. Since it just calls nanosleep
directly, it should use timespec directly instead of the typedef.
Even std::this_thread::get_id() could be made to work, the only
difficulty is that it returns a value of type std:🧵:id and
std::thread is only defined when gthreads support exists.
libstdc++-v3/ChangeLog:
* include/std/thread [!_GLIBCXX_HAS_GTHREADS] (this_thread::yield)
(this_thread::sleep_until): Define.
[!_GLIBCXX_HAS_GTHREADS] (this_thread::sleep_for): Define. Replace
use of __gthread_time_t typedef with timespec.
* src/c++11/thread.cc [!_GLIBCXX_HAS_GTHREADS] (__sleep_for):
Likewise.
* testsuite/30_threads/this_thread/2.cc: Moved to...
* testsuite/30_threads/this_thread/yield.cc: ...here.
* testsuite/30_threads/this_thread/3.cc: Moved to...
* testsuite/30_threads/this_thread/sleep_for-mt.cc: ...here.
* testsuite/30_threads/this_thread/4.cc: Moved to...
* testsuite/30_threads/this_thread/sleep_until-mt.cc: ...here.
* testsuite/30_threads/this_thread/58038.cc: Add
dg-require-sleep.
* testsuite/30_threads/this_thread/60421.cc: Likewise.
* testsuite/30_threads/this_thread/sleep_for.cc: New test.
* testsuite/30_threads/this_thread/sleep_until.cc: New test.
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.
* include/std/thread (thread:🆔:operator<=>): Define for C++20.
* testsuite/30_threads/thread/id/70294.cc: Do not take addresses of
functions in namespace std.
* testsuite/30_threads/thread/id/operators_c++20.cc: New test.
The std::jthread::get_id() function was missing a return statement.
The is_invocable check needs to be done using decayed types, as they'll
be forwarded to std::invoke as rvalues.
Also reduce header dependencies for the <thread> header. We don't need
to include <functional> for std::jthread because <bits/invoke.h> is
already included, which defines std::__invoke. We can also remove
<bits/functexcept.h> which isn't used at all. Finally, when
_GLIBCXX_HAS_GTHREADS is not defined there's no point including any
other headers, since we're not going to define anything in <thread>
anyway.
* include/std/thread: Reduce header dependencies.
(jthread::get_id()): Add missing return.
(jthread::get_stop_token()): Avoid unnecessary stop_source temporary.
(jthread::_S_create): Check is_invocable using decayed types. Add
static assertion.
* testsuite/30_threads/jthread/1.cc: Add dg-require-gthreads.
* testsuite/30_threads/jthread/2.cc: Likewise.
* testsuite/30_threads/jthread/3.cc: New test.
* testsuite/30_threads/jthread/jthread.cc: Add missing directives for
pthread and gthread support. Use VERIFY instead of assert.
From-SVN: r278402
This change avoids storing a copy of a stop_token object that isn't
needed and won't be passed to the callable object. This slightly reduces
memory usage when the callable doesn't use a stop_token. It also removes
indirection in the invocation of the callable in the new thread, as
there is no lambda and no additional calls to std::invoke.
It also adds some missing [[nodiscard]] attributes, and the non-member
swap overload for std::jthread.
* include/std/thread (jthread::jthread()): Use nostopstate constant.
(jthread::jthread(Callable&&, Args&&...)): Use helper function to
create std::thread instead of indirection through a lambda. Use
remove_cvref_t instead of decay_t.
(jthread::joinable(), jthread::get_id(), jthread::native_handle())
(jthread::hardware_concurrency()): Add nodiscard attribute.
(swap(jthread&. jthread&)): Define hidden friend.
(jthread::_S_create): New helper function for constructor.
From-SVN: r278364
* 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 std::thread constructor creates (and then moves) an unnecessary
temporary copy of each argument. Optimize it to only make the one copy
that is required.
PR libstdc++/69724
* include/std/thread (thread::_State_impl, thread::_S_make_state):
Replace single _Callable parameter with variadic _Args pack, to
forward them directly to the tuple of decayed copies.
* testsuite/30_threads/thread/cons/69724.cc: New test.
From-SVN: r271166
* include/std/future (__constrain_pkgdtask): Replace with ...
(packaged_task::__not_same): New alias template, using
__remove_cvref_t instead of decay.
* include/std/thread (thread::__not_same): Add comment.
From-SVN: r261618
The standard requires that the std::thread constructor is constrained so
it can't be called with a first argument of type std::thread. The
current implementation only meets that requirement if the constructor is
called with one argument, by using deleted overloads. This uses an
enable_if constraint to enforce the requirement for any number of
arguments.
Also add a static assertion to give a more readable error for invalid
arguments that cannot be invoked. Also simplify _Invoker to reduce the
error cascade for ill-formed instantiations with non-invocable
arguments.
PR libstdc++/84535
* include/std/thread (thread::__not_same): New SFINAE helper.
(thread::thread(_Callable&&, _Args&&...)): Add SFINAE constraint that
first argument is not a std::thread. Add static assertion to check
INVOKE expression is valid.
(thread::thread(thread&), thread::thread(const thread&&)): Remove.
(thread::_Invoke::_M_invoke, thread::_Invoke::operator()): Use
__invoke_result for return types and remove exception specifications.
* testsuite/30_threads/thread/cons/84535.cc: New.
From-SVN: r259893
* include/std/functional (_Bind_simple, _Bind_simple_helper)
(__bind_simple): Remove.
* include/std/future: Include <bits/invoke.h> instead of <functional>.
(__future_base::_Task_state::_M_run)
(__future_base::_Task_state::_M_run_delayed): Use lambda expressions
instead of __bind_simple.
(__future_base::_Task_state::_S_maybe_wrap_ref): Remove.
(async): Use thread::__make_invoker instead of __bind_simple.
* include/std/thread: Include <tuple> and <bits/invoke.h> instead of
<functional>.
(thread::_Invoker, thread::__make_invoker): Define helpers to do
INVOKE(DECAY_COPY(f), DECAY_COPY(args)...).
From-SVN: r241093
PR libstdc++/57060
* include/std/thread (operator==(thread::id, thread::id)): Do not use
__gthread_equal.
(operator<(thread::id, thread::id)): Add comment.
(this_thread::get_id()): Do not use __gthread_self for single-threaded
programs using glibc.
* testsuite/30_threads/this_thread/57060.cc: New.
From-SVN: r231289
PR libstdc++/60421
* include/std/thread (this_thread::sleep_for): Retry on EINTR.
(this_thread::sleep_until): Retry if time not reached.
* src/c++11/thread.cc (__sleep_for): Retry on EINTR.
* testsuite/30_threads/this_thread/60421.cc: Test interruption and
non-steady clocks.
From-SVN: r230183
PR libstdc++/61841
* include/std/thread (thread::_M_start_thread): Declare new overload.
(thread::thread<_Callable, _Args...>): Call new overload with an
explicit reference to pthread_create.
* src/c++11/thread.cc (thread::_M_start_thread): Add new overload.
* config/abi/pre/gnu.ver: Export new function.
From-SVN: r213922
2011-07-09 Jonathan Wakely <jwakely.gcc@gmail.com>
PR libstdc++/49668
* include/std/functional (__bind_simple): Define.
* include/std/future (_Task_setter): Parameterize by type of result
pointer instead of state object.
(_S_task_setter): Type deduction helper.
(_Task_state): Use _S_task_setter and __bind_simple.
(_Deferred_state, _Async_state): Store call wrapper directly not as
std::function. Use _S_task_setter and __bind_simple.
(_S_make_deferred_state, _S_make_async_state): Type deduction helpers.
(async): Use new functions and __bind_simple.
* include/std/mutex (call_once): Use __bind_simple.
* include/std/thread (thread): Likewise. Remove unused headers.
* src/thread.cc: Add header.
* testsuite/30_threads/async/49668.cc: New.
* testsuite/30_threads/call_once/49668.cc: New.
* testsuite/30_threads/thread/cons/49668.cc: New.
* testsuite/30_threads/thread/cons/moveable.cc: Remove unused bool.
From-SVN: r176073
2011-05-25 Paolo Carlini <paolo.carlini@oracle.com>
* include/std/thread: Use noexcept throughout per the FDIS.
* include/std/mutex: Likewise.
From-SVN: r174202
