numeric_limits<streamsize>

This code compiles and works fine with Dev C++, but MSVC.NET is giving me errors:

Code:

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#include <iostream>
...
using namespace std;
...
cin.ignore(numeric_limits<streamsize>::max(),'\n');

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MSVC reports:

Code:

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c:\SwitchConf\selectSwitch.cpp(30): error C2059: syntax error : '::'
c:\SwitchConf\selectSwitch.cpp(30): error C2065: 'numeric_limits' : undeclared identifier
c:\SwitchConf\selectSwitch.cpp(30): error C2275: 'std::streamsize' : illegal use of this type as an expression
        c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\iosfwd(22) : see declaration of 'std::streamsize'
c:\SwitchConf\selectSwitch.cpp(30): error C2589: '(' : illegal token on right side of '::'
c:\SwitchConf\selectSwitch.cpp(30): warning C4003: not enough actual parameters for macro 'max'

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Googling for numeric_limits<streamsize> turned up nothing about MSVC. What's the deal?

#include<limits>

You need to include <limits>. That's where the numeric_limits template is defined.

while we are on this subject, I tried googling for other stuff we could get limits of besides streamsize. the limits library seems kinda confusing (even MSDN didn't over this library well at all) If anyone has a link to a good site or a few examples that would be cool.

Quote:

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Originally Posted by Prelude

You need to include <limits>. That's where the numeric_limits template is defined.

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That solved most of the errors, but it's still giving me

Code:

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c:\SwitchConf\selectSwitch.cpp(31): warning C4003: not enough actual parameters for macro 'max'
c:\SwitchConf\selectSwitch.cpp(31): error C2059: syntax error : ')'
c:\SwitchConf\selectSwitch.cpp(31): error C2143: syntax error : missing ')' before '::'
c:\SwitchConf\selectSwitch.cpp(31): error C2589: '(' : illegal token on right side of '::'

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which is odd, since Dev C++ didn't complain (or perhaps that's the part that's odd).

Post a complete program that gives you the error. Also, what's the precise version of Visual C++ that you're using? .NET 2003, I would assume?

Quote:

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Originally Posted by confuted

That solved most of the errors, but it's still giving me

Code:

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c:\SwitchConf\selectSwitch.cpp(31): warning C4003: not enough actual parameters for macro 'max'
c:\SwitchConf\selectSwitch.cpp(31): error C2059: syntax error : ')'
c:\SwitchConf\selectSwitch.cpp(31): error C2143: syntax error : missing ')' before '::'
c:\SwitchConf\selectSwitch.cpp(31): error C2589: '(' : illegal token on right side of '::'

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which is odd, since Dev C++ didn't complain (or perhaps that's the part that's odd).

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Dev C++ is correct in not complaining.

Presumably you're #include'ing a MSVC header which #define's a macro named max.

If that macro is in a standard header, then you need to report a bug to Microsoft: the macro will prevent actual functions (whether class members or not) named max() from working correctly, so will prevent the standard library from working correctly.

If it is in a non-standard header that comes with MSVC (i.e. it is compiler specific) you need to work out how to avoid using that header along with standard functions (you can often - but not always - achieve that by breaking your code into multiple source files which use different headers).

A workaround (regardless of whether the problem is in a standard header or a Microsoft specific one) is this trick;

Code:

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#include <the_offending_header>
#ifdef max
#undef max
#endif

// #include the other headers you need

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Depending on what macros are #define'd in the offending header, you may need to #undef some other ones as well.

The #ifdef ... #endif wrapper for the #undef is optional, but makes the code a little safer (eg if Microsoft fixes the offending header in a future release of the compiler/library).

The min and max macros are defined within a subheader of <windows.h>, and it will most assuredly never get fixed. (Too much code using it.) You can #define NOMINMAX before including anything in order to prevent the header from defining these macros. It would be best to define it in the project options, so as to avoid source clutter.