[FFmpeg-devel] [PATCH] compat/os2threads: support static mutexes

[KO Myung-Hun]

Hi/2.

wm4 wrote:
> On Thu, 28 Dec 2017 22:03:56 +0900
> KO Myung-Hun <komh78 at gmail.com> wrote:
> 
>> ---
>>  compat/os2threads.h | 14 ++++++++------
>>  1 file changed, 8 insertions(+), 6 deletions(-)
>>
>> diff --git a/compat/os2threads.h b/compat/os2threads.h
>> index 40a119ffe1..2177a033ec 100644
>> --- a/compat/os2threads.h
>> +++ b/compat/os2threads.h
>> @@ -1,5 +1,5 @@
>>  /*
>> - * Copyright (c) 2011 KO Myung-Hun <komh at chollian.net>
>> + * Copyright (c) 2011-2017 KO Myung-Hun <komh at chollian.net>
>>   *
>>   * This file is part of FFmpeg.
>>   *
>> @@ -46,9 +46,11 @@ typedef struct {
>>  
>>  typedef void pthread_attr_t;
>>  
>> -typedef HMTX pthread_mutex_t;
>> +typedef _fmutex pthread_mutex_t;
>>  typedef void pthread_mutexattr_t;
>>  
>> +#define PTHREAD_MUTEX_INITIALIZER _FMUTEX_INITIALIZER
>> +
>>  typedef struct {
>>      HEV event_sem;
>>      HEV ack_sem;
>> @@ -98,28 +100,28 @@ static av_always_inline int pthread_join(pthread_t thread, void **value_ptr)
>>  static av_always_inline int pthread_mutex_init(pthread_mutex_t *mutex,
>>                                                 const pthread_mutexattr_t *attr)
>>  {
>> -    DosCreateMutexSem(NULL, (PHMTX)mutex, 0, FALSE);
>> +    _fmutex_create(mutex, 0);
>>  
>>      return 0;
>>  }
>>  
>>  static av_always_inline int pthread_mutex_destroy(pthread_mutex_t *mutex)
>>  {
>> -    DosCloseMutexSem(*(PHMTX)mutex);
>> +    _fmutex_close(mutex);
>>  
>>      return 0;
>>  }
>>  
>>  static av_always_inline int pthread_mutex_lock(pthread_mutex_t *mutex)
>>  {
>> -    DosRequestMutexSem(*(PHMTX)mutex, SEM_INDEFINITE_WAIT);
>> +    _fmutex_request(mutex, 0);
>>  
>>      return 0;
>>  }
>>  
>>  static av_always_inline int pthread_mutex_unlock(pthread_mutex_t *mutex)
>>  {
>> -    DosReleaseMutexSem(*(PHMTX)mutex);
>> +    _fmutex_release(mutex);
>>  
>>      return 0;
>>  }
> 
> LGTM. Does this actually switch to futex-like light weight mutexes? (I
> don't know anything about OS/2, but it does sound like PHMTX was the
> equivalent of a win32 HANDLE mutex kernel object, that required kernel
> entry on each lock/unlock, while _fmutex is possibly like Vista+ SRWs.)

_fmutex is not futex-like light-weight mutex. Unlike HMTX, however,
_fmutex supports static mutexes.

-- 
KO Myung-Hun

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