[M3devel] cvsup

[Olaf Wagner]

Quoting Daniel Solaz <m3 at sol42.com>:

> On 16 Mar 2010, at 20:32, Tony Hosking wrote:
>> fork should still work with pthreads.  Why wouldn't it?
> Chapter 6.1 of Butenhof's pthreads book deals with this, and well,   
> it is a mess.  According to him only the calling thread exists on   
> return from fork() in the child process, but the other pthread   
> *states* (mutexes, conditions, data keys, etc.) are replicated as   
> well.  And I'm sure the details vary from system to system.
> This is the chapter's first sentence: "Avoid using fork in a   
> threaded program (if you can) unless you intend to exec a new   
> program immediately."

Is this about kernel threads or user level threads? Or about a specific
implementation of one or the other?

I don't know the book, but I always thought about pthreads as being the
POSIX specification of threads, and I don't think there's anything
in that relating to fork, AFAIR, but that was years ago.

Can anyone enlighten us about the POSIX specs and if they define the
semantics of fork in presence of threaded processes? Or does it really
boil down to the above `avoid it if you can'?

Olaf
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