RE: Using pthread_t as a key in a map

["Robert Kindred" <RKindred at SwRI dot edu>]

I have gotten a lot of my tricks from a book which has the acronym of POSA2.
This stands for "Pattern-Oriented Software Architecture" Volume 2, by
Douglas Schmidt.  It is a book about concurrent and network programming.
This is the book that explains a lot of the design of ACE (Adaptive
Communiations Environment).  However, I do not use ACE.

Robert Kindred

> -----Original Message-----
> From: pthreads-win32-owner@sourceware.org
> [mailto:pthreads-win32-owner@sourceware.org]On Behalf Of Paolo Brandoli
> Sent: Monday, May 15, 2006 6:57 AM
> To: pthreads-win32@sourceware.org
> Subject: Re: Using pthread_t as a key in a map
>
>
> Hi Will,
>
> What I'm trying to do is to order the pthread_t pointers so I can
> simulate the windows function "WaitForMultipleObjects"; I have to
> order the pthread_t in a consistent way before attempting to lock
> several mutexes at once.
>
> The way the pthread_t is defined in the library doesn't allow to use
> the < and > operators; those operators can be used when pthread_t is
> defined as a pointer (like in the pthreads implementation on posix
> systems) and not as a structure containing a pointer (as in
> win32-pthread).
>
> I defined the operator for ptw32_handle_t, but it works for pthread_t
> (since it is a synonim for ptw32_handle_t).
>
> Anyway your considerations are right since this breaks the compilation
> on C compilers. On C++ compilers it just remove the errors when I try
> to compare two pthread_t values.
>
> I'm trying to find a more elegant solution, but I'm just staring at
> the monitor and nothing pops up in my brain.
>
> Paolo Brandoli
>
> On 5/15/06, Will Bryant <will.bryant@ecosm.com> wrote:
> > Hi Paolo,
> >
> > Bear in mind that pthreads-win32 is written in C, and operator
> > overloading is a C++ feature, so adding that would prevent
> > pthreads-win32 from compiling with C apps.
> >
> > One alternative is to make a custom comparator type and use that in the
> > map declaration - or you could even simply move those operator overloads
> > to your own units (they don't have to be defined where the type being
> > compared is declared, as long as they've visible at the point where
> > they're used - ie. your map declaration).
> >
> > But bear in mind that in any case, making use of the ptw32_handle_t type
> > makes your code nonportable, and since portability is generally the
> > reason one is using pthreads-win32 in the first place, this is perhaps
> > not the best design for general use.
> >
> > Will
> >
> >
> > Paolo Brandoli wrote:
> > > I have a source code that uses the pthread_t as a key in a std::map.
> > > Because pthread-win32 defines pthread_t as a structure, the
> > > compilation fails.
> > >
> > > I added the following lines in my pthread.h header in order to allow
> > > the usage of pthread_t in the map:
> > >
> > > bool operator < (const ptw32_handle_t& left, const
> ptw32_handle_t& right)
> > > {
> > >    return left.p < right.p;
> > > }
> > >
> > > bool operator > (const ptw32_handle_t& left, const
> ptw32_handle_t& right)
> > > {
> > >    return left.p > right.p;
> > > }
> > >
> > > Bye
> > > Paolo Brandoli
> > > http://www.puntoexe.com
> > >
> >
> >
> > --
> > Will Bryant
> >
> >
> >
> >
>