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Message-ID: <233f8671-c1af-4587-bb83-a206a7e90090@gmail.com>
Date: Thu, 30 May 2024 12:28:16 +0200
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Subject: Re: [PATCH v2] Cygwin: pthread: Fix a race issue introduced by the
 commit 2c5433e5da82
To: Bruno Haible <bruno@clisp.org>, Takashi Yano <takashi.yano@nifty.ne.jp>,
        cygwin@cygwin.com
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 <2073558.3YGTXZJOeS@nimes>
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From: Noel Grandin via Cygwin <cygwin@cygwin.com>
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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

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