Compiling SymbolicC++ - operator , is ambiguous

Question

I'm trying to compile the SymbolicC++ library in VC++ 2010 Express (there is special VS project in the distribution), but it gives a lot of errors in system headers, related to operator,. For example:

1>C:\Program Files\Microsoft Visual Studio 10.0\VC\include\xlocmon(410): error C2593: 'operator ,' is ambiguous

For this code in a system header:

if (_Str[0] < _E0 || _E0 + 9 < _Str[0])
    _Str2 += '-', ++_Off;

Why? How to compile it?

try and change that `,` to a `;`. bad practise to use the `,` to avoid to write a `{}` block. — vulkanino, Mar 08 '12 at 15:10
@vulkanino, we all still do it from time to time though, don't we :) — Blindy, Mar 08 '12 at 15:11
I honestly can say I have never done it nor considered it. I would wrap a single statement in `{}` before trying to abuse the `,` that way. — Joe, Mar 08 '12 at 15:19
And using the builtin sequence operator like that might be against reordering optimizations. +1 PlasmaHH. — Sebastian Mach, Mar 08 '12 at 16:32
RankoR, Which approach did you take to solve the problem? Reorder the header files? Or edit ``? — dharmatech, Nov 25 '12 at 22:44

user7116 · Accepted Answer · 2012-03-08T15:46:33.177

5

Apparently, SymbolicC++ has overloaded operator, in such a manner that a downstream include has been affected.

You should reorder your includes such that SymbolicC++'s include comes last:

#include <iostream>
#include <vector>

// don't want to monkey with our other headers
#include "symbolicc++.h"

This isn't to say the code in the <xlocmon> header isn't suspect, that sort of ~~abuse~~usage of the comma operator is asking for trouble.

edited Mar 08 '12 at 15:46

answered Mar 08 '12 at 15:11

user7116

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Interesting, well then SymbolicC++ abused the comma operator in a manner that caused a downstream include to barf. – user7116 Mar 08 '12 at 15:25
Basically you need to take care to ensure `symbolicc++.h` does not get included before any of the system header files. – user7116 Mar 08 '12 at 16:35
@RankoR: Learn to judge by content, not by badge ;) – Sebastian Mach Mar 08 '12 at 16:50
@sixlettervariables We're you able to get the SymbolicC++ library to actually build? I'm running into the same issue, but am not sure which headers to reorder. – dharmatech Nov 25 '12 at 22:47
The file `verylong.h` includes `` which in turn includes ``. The trouble is that `symbolicc++.h` includes `verylong.h` and later includes `symbolicc++.h` 3 more times. It seems like it would be quite tricky to reorder the headers in a way that doesn't trigger the ambiguity error. – dharmatech Dec 12 '12 at 07:38

score 2 · Answer 2 · answered Dec 12 '12 at 07:03

2

Here's another workaround which avoids having to modify <xlocmon>.

The dependency on <xlocmon> is via verylong.h which includes <iomanip> which in turn includes <xlocmon>. In verylong.h, comment out the line:

#include <iomanip>

After doing this, the build completes successfully on my system (Windows 7, Visual C++ 2010 Express).

answered Dec 12 '12 at 07:03

dharmatech

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For detailed instructions on getting SymbolicC++ to run in Visual C++ 2010 Express, see [this StackOverflow](http://stackoverflow.com/questions/10679416/how-do-you-install-symbolic-c-on-visual-studio-2010/13775602#13775602) answer. – dharmatech Dec 12 '12 at 07:48

score 2 · Answer 3 · answered Mar 08 '12 at 15:10

2

When in doubt, add parentheses:

    if (_Str[0] < _E0 || _E0 + 9 < _Str[0])
        (_Str2 += '-'), ++_Off;

Or simply write proper C++ code:

    if (_Str[0] < _E0 || _E0 + 9 < _Str[0])
    {
        _Str2 += '-';
        ++_Off;
    }

answered Mar 08 '12 at 15:10

Blindy

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While I would like to avoid editing the system header ``, this solution does indeed work and SymbolicC++ 3.35 builds successfully for me (Visual C++ 2010 Express). – dharmatech Nov 26 '12 at 07:25

score 0 · Answer 4 · answered Mar 08 '12 at 15:11

0

We have no idea what their operator, is doing, so this may well not be valid, but that's a weird way to do things -- the following is equivalent and less weird:

    if (_Str[0] < _E0 || _E0 + 9 < _Str[0]) {
        _Str2 += '-';
        ++_Off;
    }

answered Mar 08 '12 at 15:11

Ernest Friedman-Hill

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score 0 · Answer 5 · answered Mar 08 '12 at 15:16

0

The comma operator doesn't make any sense in 90% of the cases. The solution is to hit whoever wrote that code in the head with a blunt object, then rewrite it as:

if (_Str[0] < _E0 || _E0 + 9 < _Str[0])
{
  _Off++;
  _Str2 += '-';
}

answered Mar 08 '12 at 15:16

Lundin

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Compiling SymbolicC++ - operator , is ambiguous

5 Answers5

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