Side effects of open system call

[Valdis.Kletnieks at vt.edu]

On Thu, 20 Feb 2014 20:36:44 +0530, Rahul Bedarkar said:

> "Often the open(2) call has unwanted side effects, that can be avoided
>        under Linux by giving it the O_NONBLOCK flag."
>
> I have seen open man page but can't find what are side effects of open.

Well, for starters, the open() call can block while trying to open a hardware
device that isnt ready, thus hanging the entire process. For added joy,
remember that signals are delivered when a process inside a syscall finally
returns to userspace - which means that your hung process may be unkillable
even by 'kill -9'.

Most people would call that an unwanted side effect. :)
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