What is __thread tls?

[Zera William Holladay]

On Mon, 14 Mar 2005, Matthew Dillon wrote:
[cut]
>     This feature could be used by, well, just about every library.  For example,
>     it would allow us to clean up how 'errno' works in a threaded environment.
>     It would allow standard libc calls such as ctime() and localtime() work
>     properly in a threaded environment, and it would greatly simplify the job
>     of writing threaded library code.

I was under the impression that each pthread has its own errno???  Perhaps
I am not understanding the context.  I'm writing my first threaded
application so I had best get this straight sooner rather than later.

-Zera