I believe[1][2] that 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. [1] https://en.cppreference.com/w/cpp/thread/condition_variable/wait_for [2] https://github.com/cplusplus/draft/blob/master/source/threads.tex --- libstdc++-v3/ChangeLog | 3 +++ libstdc++-v3/include/std/condition_variable | 5 +++-- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 4657af7..432cb84 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,4 +1,7 @@ 2018-07-20 Mike Crowe <m...@mcrowe.com> + * include/std/condition_variable (wait_for): Use steady_clock. + +2018-07-20 Mike Crowe <m...@mcrowe.com> * include/std/condition_variable (wait_until): Only report timeout if we really have timed out when measured against the caller-supplied clock. diff --git a/libstdc++-v3/include/std/condition_variable b/libstdc++-v3/include/std/condition_variable index a2d146a..ce58399 100644 --- a/libstdc++-v3/include/std/condition_variable +++ b/libstdc++-v3/include/std/condition_variable @@ -65,6 +65,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION class condition_variable { typedef chrono::system_clock __clock_t; + typedef chrono::steady_clock __steady_clock_t; typedef __gthread_cond_t __native_type; #ifdef __GTHREAD_COND_INIT @@ -142,11 +143,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION wait_for(unique_lock<mutex>& __lock, const chrono::duration<_Rep, _Period>& __rtime) { - using __dur = typename __clock_t::duration; + using __dur = typename __steady_clock_t::duration; auto __reltime = chrono::duration_cast<__dur>(__rtime); if (__reltime < __rtime) ++__reltime; - return wait_until(__lock, __clock_t::now() + __reltime); + return wait_until(__lock, __steady_clock_t::now() + __reltime); } template<typename _Rep, typename _Period, typename _Predicate> -- git-series 0.9.1 BrightSign considers your privacy to be very important. The emails you send to us will be protected and secured. Furthermore, we will only use your email and contact information for the reasons you sent them to us and for tracking how effectively we respond to your requests.
