[Bug libstdc++/70276] Writing to standard output concurrently through `std::cout` triggers a datarace

[stefan at vectorfabrics dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70276

--- Comment #2 from Stefan Holdermans <stefan at vectorfabrics dot com> ---
Note that the C++11 Standard (§27.4.1) prescribes that

"Concurrent access to a synchronized (§27.5.3.4) standard iostream object’s
formatted and unformatted input (§27.7.2.1) and output (§27.7.3.1) functions or
a standard C stream by multiple threads shall not result in a data race
(§1.10)."