Jeroen T. Vermeulen wrote:
> Now, there's one thing here that makes me curious: this is the first time
> I've ever heard of these macros ever being _needed_ for anything. First
> time in fact I heard of even a theoretical possibility of them making any
> difference at all (apart from breaking things, of course). Practically
> all code I can think of should just work as normal if one replaced the
> macros with the standard functions, and a lot of proper code would
> suddenly start working. So does afxtempl.h explicitly check for the
> presence of min() and max() macros, and refuse to work if they're not
> there? If so, why? If not, what goes wrong if they're not there?
The problem with std::min() and std::max() is that they require two
exactly equal arguments. The following code:
short s = 5;
int i = 3;
int result = std::max(s,i);
fails with these errors:
D:\Documents and Settings\bsamwel\Local Settings\Temp\tcppsrc.cpp(5) :
error C2780: 'const _Ty &std::max(const _Ty &,const _Ty &,_Pr)' :
expects 3 arguments - 2 provided
C:\Program Files\Microsoft Visual Studio .NET
2003\Vc7\include\xutility(1250) : see declaration of 'std::max'
D:\Documents and Settings\bsamwel\Local Settings\Temp\tcppsrc.cpp(5) :
error C2782: 'const _Ty &std::max(const _Ty &,const _Ty &)' : template
parameter '_Ty' is ambiguous
C:\Program Files\Microsoft Visual Studio .NET
2003\Vc7\include\xutility(1242) : see declaration of 'std::max'
could be 'int'
or 'short'
I could do without the first error, but the second error is pretty
clear: it can't deduce the template argument. This is the general cause
of problems when using std::min and std::max instead of macros.
Cheers,
Bart
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