threads in 5.4 and 5.5

[Dan Nelson]

In the last episode (May 09), Mark Kent said:
> What is the canonical way to compile programs that use posix threads
> on freebsd 5.4+, with gcc?
> 
> I've seen comments that say that -pthread, used in 4.x, should go
> away for 5.x.  But, for example, /usr/ports/security/openssl uses
> -pthread.

-pthread is still the recommended way, I think.

> And what does it mean when a program works with one thread
> library and not another?  I've got a case like this:
> 
> libpthread.so.1: chew up cpu, then SEGV
>     libthr.so.1: chew up cpu, but works!
>     libc_r.so.5: works great!
> 
> This is changed with libmap.conf.
> 
> Does this point to any particular shady coding practice?

Could point to a race between two threads that is only lost when the
threads actually run on two CPUs. libc_r switches between threads on a
single processor, where libthr and libpthread allow multiple threads to
execute at once.

-- 
	Dan Nelson
	dnelson at allantgroup.com