Re: [boost] Hello?

From: David Abrahams (dave_at_[hidden])
Date: 2005-09-15 12:53:41

"Robert Ramey" <ramey_at_[hidden]> writes:

> I would call your attention to the code in serialization.hpp - line 108 
> "layer 3".  I believe that this code actually considered this problem.  By 
> using an argument from the boost::serialzation namespace It guarenteed that 
> the correct overload would be found on the second phase of two phase lookup 
> on compilers supporting ADL (all those that implement two-phase lookup).  If 
> I remember correctly, I also studied the rules that governed the conversion 
> from boost::serialization::version_type to const unsigned integer and this 
> information was used to make the process work.  I left the note you see in 
> the documentation.  This resolved the compilation errors I was having with 
> compilers which implement two-phase lookup so naturally I took this a 
> confirmation that I understood the details.  Unfortunately it was some time 
> ago and and after I thought I resolved the problems generated by two-phase 
> lookup I moved on to other problems.  So I thought I understood it.  Of 
> course now I'm not so sure.  I forgot the details of my solution but did 
> remember the amount of detail I had to plow through.

Yikes!  

**** I owe you an abject apology. I'm very sorry for wasting all  ****
**** this time and energy.  I should have looked at the code much **** 
**** sooner.  That's a very clever technique.                     ****

Provided the file_version parameter is never templatized, that trick
works and it's always okay to overload in boost::serialization.

>> It's hard for me to feel very sympathetic.  You have the online
>> compiler.
>
> I don't think its practical to use the online compiler to compile code that 
> requires scores of files.

I've done it.  Just preprocess and paste.

>> You could find out what the switches are (--no-microsoft
>> and/or --no-microsoft-bugs) to turn on 2-phase lookup on your local
>> installation of comeau and do some experiments.
>
> I can and I will.  I had no reason to suppose that it was turned off for 
> boost (presumably in the toolset).  I just assumed that build tools would be 
> setup to maximize compiler conformance with the standard.   Perhaps 
> presumptuous on my part but I have to make some reasonable assumptions or 
> I'll never get anything done.

The problem is that como still doesn't have a switch that turns off
MS bug compatibility but leaves on the extensions needed to compile MS
system headers.  Without the ability to process Windows.h, many Boost
libraries wouldn't compile.

>> That would still be a big improvement on the status quo.
>
> OK I'll just make this alteration in that section.  Halleluhuh

At this point, if you make any change I think you should add a note
for those of us who are too clever by half, saying that, yes, it's
really okay to overload in boost::serialization, and describing the
trick used.

So sorry,

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com