std::mutex bug: Windows handle growth

[Noel Grandin]

On 3/17/2026 4:08 PM, Corinna Vinschen via Cygwin wrote:
> On Mar 17 09:06, Noel Grandin via Cygwin wrote:
> No, checking trylock() is correct.  pthread_mutex_destroy() must not
> destroy a busy mutex.  trylock() returns != 0 if the lock is busy.
> 

Aha! I misread that code.

> Given the implementation of std::mutex is based on pthread_mutex,
> Frank's code is wrong, or at least somewhat borderline.  The mutex
> should first be unlocked before leaving do_something().
> 

std::lock_guard will unlock in its destructor, so it should unlock before leaving do_something().

Regards, Noel Grandin.