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From: "Paolo Brandoli" <paolo.brandoli@gmail.com>
To: pthreads-win32@sourceware.org
Subject: Re: Using pthread_t as a key in a map
Date: Mon, 15 May 2006 11:57:00 -0000	[thread overview]
Message-ID: <553911630605150457h36bc27d9w66eff467888e69ea@mail.gmail.com> (raw)
In-Reply-To: <4467E5FA.3020300@ecosm.com>

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
>
>
>
>

  reply	other threads:[~2006-05-15 11:57 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-09 20:55 Paolo Brandoli
2006-05-15  2:23 ` Will Bryant
2006-05-15 11:57   ` Paolo Brandoli [this message]
2006-05-15 14:02     ` Robert Kindred
2006-05-15 14:24   ` Ross Johnson
2006-05-16  1:17     ` Ross Johnson
2006-05-16 14:09       ` Paolo Brandoli

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