Re: reason for code like this: "do { something } while (0)"

["Jesper Juhl" <jesper.juhl@xxxxxxxxx>]

On 15/05/06, Rajat Jain <rajat.noida.india@xxxxxxxxx> wrote:
> Hi,
>
> I'm asking a pretty amateur question.
>
> I've come accross code like this huge number of times in the kernel:
>
> #define __set_task_state(tsk, state_value)              \
>         do { (tsk)->state = (state_value); } while (0)
>
> What is the reason to use do while loop if it is only meant to be
> executed just once? Why not a simple:
>
> #define __set_task_state(tsk, state_value)              \
>         { (tsk)->state = (state_value); }

http://www.kernelnewbies.org/FAQ/DoWhile0

--
Jesper Juhl <jesper.juhl@xxxxxxxxx>
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