[fpc-pascal] Various Darwin problems

Jonas Maebe jonas.maebe at elis.ugent.be
Tue Oct 11 14:35:16 CEST 2005


On 11 okt 2005, at 14:25, Felipe Monteiro de Carvalho wrote:

>>> The sleep was changed from select to nanosleep. It seems OS X
>>> doesn't accept
>>> sleeps smaller than 10ms.
>>
>> That is not true. This program takes half a second on my machine:
>
> This only happens because you are getting a very big time period on
> your test. Sleep, nanosleep and all other timing procedures are simply
> *not* reliable when you want a microsecond or 1milisecond precision.
> This kind of precision is achieved throught other means, such as
> special device drivers, interruptions, real-mode, etc.

You're completely right they are not reliable. Also, you must always  
remember that nanosleep() can return before it has waited for the  
specified time (that's what the second parameter is for) because of  
delivery of a signal.


Jonas



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