Re: [boost] [test] test/included min max macro issue

From: Paul A Bristow (pbristow_at_[hidden])
Date: 2006-06-26 07:57:30

|  -----Original Message-----
|  From: boost-bounces_at_[hidden] 
|  [mailto:boost-bounces_at_[hidden]] On Behalf Of Martin Bonner
|  Sent: 26 June 2006 11:59
|  To: boost_at_[hidden]
|  Subject: Re: [boost] [test] test/included min max macro issue
|  
|  ----Original Message----
|  From: boost-bounces_at_[hidden]
|  [mailto:boost-bounces_at_[hidden]] On Behalf Of Paul A Bristow
|  Sent: 24 June 2006 14:34 To: boost_at_[hidden]
|  Subject: Re: [boost] [test] test/included min max macro issue
|  
|  > A further quick question on this problem.
|  > 
|  > It is my custom (having a strong view that it aids readers -
|  > including me - 
|  > of my programs) to write
|  > 
|  > #include <limits>
|  >   using std::numeric_limits;
|  > 
|  > How do I avoid min/max macro problems when writing, for example,
|  > 
|  >   return numeric_limits<double>::max(); 
?
|  >From the website:
|  >>  > #  If you want to call std::numeric_limits<int>::max(), use
|  >>  > (std::numeric_limits<int>::max)() instead.> 
|  
|  The basic rule is that you must never have the (pp-)tokens 
|  "max" and "("
|  one after the other.  If you do, the preprocessor will try 
|  to expand the max macro.
|  
|  The solution is to wrap the function name in parens, so what 
|  you would write is:
|  
|  	return (numeric_limits<double::max)();
|  
|  That means the preprocessor sees "max" and ")", and doesn't try to
|  expand the macro.

Thanks, I am now better disambiguated - if at present macro vulnerable ;-(

Perhaps Tonto can add this to the Boost Guidelines ;-)

Paul

---
Paul A Bristow
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