[fpc-devel] Why FreeBSD sem_init() works different to Linux?

[Sven Barth]

Am 04.02.2013 15:02, schrieb Henry Vermaak:
> On Mon, Feb 04, 2013 at 02:54:10PM +0100, Sven Barth wrote:
>> Am 04.02.2013 13:40, schrieb Henry Vermaak:
>>> On Mon, Feb 04, 2013 at 11:47:48AM +0000, Graeme Geldenhuys wrote:
>>>> Hi,
>>>>
>>>> I found another problem with Semaphores between FreeBSD and Linux.
>>>>
>>>> Attached is my test project. Again, it is similar code used in tiOPF.
>>>>
>>>> For some reason under FreeBSD, it *always* zeros the variable that holds
>>>> the Max Pool Size value passed in to sem_init()'s third parameter. This
>>>> means that if I try and us that variable anywhere after the sem_init()
>>>> call, like when I want to destroy the semaphore, I can't because the
>>>> variable now holds the value 0.
>>> FPC's definition of the semaphore struct is probably wrong for FreeBSD.
>>> Currently, it's:
>>>
>>> sem_t = cint;
>> You are in so far right that the declaration is incorrect, but in
>> trunk it looks like this:
>>
>> === code begin ===
>>
>> sem_t_rec = record end;
>> sem_t = ^sem_t_rec;
>>
>> === code end ===
> Indeed, but trunk pthread.inc looks different from this:
>
> sem_t = record
> 	magic   : cuint32;
> 	lock    : pthread_mutex_t;
> 	gtzero  : pthread_cond_t;
> 	count   : cuint32;
> 	nwaiters: cuint32;
> 	semid   : semid_t;
> 	sysse   : cint;
> 	entry   : psem_t;
> 	backpointer : ppsem_t;
> 	spare : array[0..SEM_SAFE] of char;
> end;
>
> Since the definition of TSemaphore is in this file, this definition will
> be used?
The rtl/freebsd/pthread.inc is only used in the implementation section 
of rtl/unix/cthreads.pp. And if we fix the sem_t type then this 
declaration can be removed again (it will then use UnixType.sem_t which 
is located in rtl/inc/ptypes.inc).

Regards,
Sven