usleep

[Robert Woolley]

On Mon, 25 Feb 2008 10:39:59 +0100
"Heiko Wundram (Beenic)" <wundram at beenic.net> wrote:

> Am Montag, 25. Februar 2008 10:10:56 schrieb Sharad Chandra:
> > So does it mean, freebsd has limitation. sleeping will only work
> > for its value more than 1 milli sec because % of +- error value is
> > comparitivly low? I am curious to know, is there any method which
> > sleeps for few microseconds. Some one please give me link where to
> > look for "select".
> 
> No, this does not mean that FreeBSD has a limitation, but rather that
> FreeBSD is not a real-time operating system. You'll see the similar
> behaviour on pretty much any other operating system that is _not_ a
> RTOS 

It's actually not a distinguishing feature of RTOSs. I haven't worked on
them for a few years, but when I did, both pSOS and VxWorks had this
limitation. The important thing is that RTOSs handle interrupts
well. In traditional real-time software, sleeping is something that
happens in non-critical background tasks.