--- Halil Demirezen <demirh@bilmuh.ege.edu.tr> wrote:
>
> in linux/spinlock.h the spinlocks are defined
> and i want to know what kind of a reasonability does it have to
> define
> spin_lock and spin_unlock in the following way.
>
>
> #define spin_lock(lock) do {} while(0)
> #define spin_unlock(lock) (void)...
>
The do{}while(0) is explained in the FAQ. You'll find a link to the
FAQ at the bottom of this message.
>
> to be shorty, what is the actual aim of spin_lock and spin_unlock ,
> spin_lock_irq spin_unlock_irq.....etc
>
> and what is the aim of semaphores.
>
A discussion of spinlocks can be found at
http://www.xml.com/ldd/chapter/book/ch09.html#t8. Scoll down to
"Using Spinlocks".
<snip>
Harmony,
--Christine
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