[PATCH v2] Cygwin: pthread: Fix a race issue introduced by the commit 2c5433e5da82

[Noel Grandin]

On 5/30/2024 11:15 AM, Bruno Haible wrote:
> 
> Still: Does ReleaseSRWLockExclusive notify other threads?
> 

Of course? How else would a lock work, it must release other waiters?

It might not be a fair lock though, which is not a problem for this situation, which does not require fair locking.


> Functionally, the INIT_ONCE looks interesting. But, like Takashi Yano mentioned,
> how would you make it fit into a pthread_once_t that is defined as
>    struct { pthread_mutex_t mutex; int state; }
> ?

Something like:

struct once {
    union {
       pthread_mutex_t old_mutex_field_for_size_compatibility;
       SRWLOCK lock = SRWLOCK_INIT;
     };
     int state;
};

Regards, Noel Grandin