Re: Mutexes

[Ben Pfaff]

John Darrington <address@hidden> writes:

> On Sun, Apr 19, 2009 at 09:05:07PM -0700, Ben Pfaff wrote:
>      John Darrington <address@hidden> writes:
>      
>      > On Sun, Apr 19, 2009 at 08:26:57PM -0700, Ben Pfaff wrote:
>      >      John Darrington <address@hidden> writes:
>      >      
>      >      > Any objections if I check in some thread safety changes to the 
> lower
>      >      > levels, such as the attached patch ?
>      >      >
>      >      > I don't think there's going to be a multi-threaded pspp for 
> production
>      >      > use any time soon, but I've been doing some experiments in 
> order to
>      >      > find out what some of the issues are.
>      >      
>      >      Could we put this into a separate branch?  I'm nervous about
>      >      adding unneeded dependencies.
>      >
>      > It doesn't need any additional dependencies, unless you count an extra
>      > gnulib module as a dependency.
>      
>      Won't the gnulib module will cause our binaries to link against
>      new libraries, e.g. libpthread on Linux?
>      
>      At any rate, this will change some very cheap operations, such as
>      incrementing a value, into relatively expensive ones.
>
> I thought they were supposed to do nothing if a thread library wasn't 
> specified.  

But the "lock" module is at least documented to require linking
against a thread library.  Maybe it doesn't really require it,
but...

I'm not against making PSPP thread-safe, but I'm against it if we
aren't actually threading PSPP.
-- 
Ben Pfaff 
http://benpfaff.org