https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91486
--- Comment #2 from John Salmon <john.salmon at deshaw dot com> --- The same incorrect logic that was fixed in bug 68519 is present in the implementations of future::wait_for and shared_timed_mutex::wait_for. The fix should be the same: explicitly duration_cast the __rtime argument to __clock::duration before adding to __clock::now(). Fixes are required in shared_mutex and bits/atomic_futex.h. The attached code demonstrates the problem. wait_for either waits too long or too short. Output is: drdws0134$ garden with -m gcc/8.1.0-01c7/bin g++ -std=c++14 futurewait.cpp -pthread && ./a.out ERROR - future::wait_for took too short: t1 looping: 0 milliseconds 0 second t2 looping: 0 second ERROR - shared_timed_mutex::try_lock_shared took too short: 0 milliseconds t2 looping: 1 second t1 looping: 1 second t2 looping: 2 second t1 looping: 2 second t2 looping: 3 second t1 looping: 3 second t2 looping: 4 second t1 looping: 4 second
