[boost] Re: min, max, GCC 2.95.3, and STLport

From: Eric Niebler (eric_at_[hidden])
Date: 2004-06-30 19:22:09

Martin Wille wrote:
> Doug Gregor wrote:
> 
>> The new handling of min/max seems to break under GCC 2.95.3 with 
>> STLport. I'm not quite sure _why_ it doesn't work (I don't have the 
>> compiler around), but you can see the failure here:
>>
>>     http://tinyurl.com/ytdlf
>>
>> Perhaps someone with that compiler/lib combination could get 
>> preprocessed output for the problem area so we could see what's 
>> happening?
> 
> 
> Maybe this experiment sheds some light on the problem:
> I tried this code with gcc-2.95.3 and STLport:
> 
> #include <boost/minmax.hpp>
> 
> int foo()
> {
>     BOOST_USING_STD_MIN();
>     return min BOOST_PREVENT_MACRO_SUBSTITUTION(3, 4);
> }
> 
> namespace notboost
> {
>     template <typename T>
>     T const &
>     proxy_min(T const &p, T const &q)
>     {
>         BOOST_USING_STD_MIN();
>         return min BOOST_PREVENT_MACRO_SUBSTITUTION(p, q);  // line 16
>     }
> }
> 
> int bar()
> {
>     return notboost::proxy_min(3, 4);                       // line 22
> }
> 
> 
> namespace test
> {
>     int baz()
>     {
>         BOOST_USING_STD_MIN();
>         return min BOOST_PREVENT_MACRO_SUBSTITUTION(3, 4);
>     }
> }
> 
> int main() { foo(); bar(); test::baz(); }
> 
> 
> The compiler emits these error messages:
> min.cpp: In function `const int & notboost::proxy_min<int>(const int &, 
> const int &)':
> min.cpp:22:   instantiated from here
> min.cpp:16: `min' undeclared (first use this function)
> min.cpp:16: (Each undeclared identifier is reported only once
> min.cpp:16: for each function it appears in.)
> 
> 
> So it looks like gcc 2.95.3 doesn't handle the using declaration
> inside template functions properly.
> 
> 
> HTH,
> m

Ugh. Thanks Martyn. Can you tell me if there is something funny about 
the way STLPort defines std::min/max? Does it use macros? Or are they 
defined globally and imported into the std:: namespace with using 
declarations?

In the worst case, I suppose for this compiler/library combination we 
can import std::min/max into the boost namespace with a using 
declaration and make BOOST_USING_STD_MIN() expand to nothing. Martyn, 
can you try that and see if it works?

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com