compiler warning on vc 2008

Wed Oct 07, 2009 9:27 am

compiler warning on vc 2008

Wed Oct 07, 2009 9:27 am

Hi,
I'm using vs 2008 and eigen 2.06. When compiling with warning level 4 (/W4)on, I get the following compiler warning in Functors.h, ln 282:

Code: Select all: warning C4512: 'Eigen::ei_scalar_multiple_op<Scalar>' : assignment operator could not be generated with [ Scalar=double ]

According to MS' website, one could do the following:
1. Explicitly define an assignment operator for the class.
2. Remove const from the data item in the class.
3. Use the #pragma warning statement to suppress the warning.
Option 3 is just pragmatic, but I hate doing this kind of stuff unless i don't have to.
Any thoughts?
best regards,
grinderfox

Wed Oct 07, 2009 11:16 am

Re: compiler warning on vc 2008

Wed Oct 07, 2009 11:16 am

I fixed all those warnings in the devel branch. Since they are only occuring with /W4 enabled and since they are not really important, we did not backport them as of now.

In case you desparately need the backport please let me know.

We fixed by adding

Code: Select all: Class& operator=(const Class&);

to the private section of clases where this warning occurs.

Regards,
Hauke

Wed Oct 07, 2009 12:07 pm

Re: compiler warning on vc 2008

Wed Oct 07, 2009 12:07 pm

Hauke wrote:In case you desparately need the backport please let me know.

It depends, when will the 2.1 be out?

thanx for the quick fix...
Just to be sure: for example, if the warning was tied to class CwiseNullaryOp, then all I have to do is add
private:
CwiseNullaryOp& operator=(const CwiseNullaryOp&);
at the end of the CwiseNullaryOp class def?

Wed Oct 07, 2009 12:26 pm

Re: compiler warning on vc 2008

Wed Oct 07, 2009 12:26 pm

grinderfox wrote:I have to do is add
private:
CwiseNullaryOp& operator=(const CwiseNullaryOp&);
at the end of the CwiseNullaryOp class def?

That's right. It nicely emphasizes that the operator is not even generated by the compiler - otherwise you would receive compile errors.

Regarding the release roadmap I am the wrong person to ask - we need some feedback from Gael or Benoit.

- Hauke

Wed Oct 07, 2009 12:38 pm

Re: compiler warning on vc 2008

Wed Oct 07, 2009 12:38 pm

The next major version is still far away and will have a more "interesting" name than "eigen 2.1"

I can't speak about this particular issue, I don't have MSVC. We've backported bigger ones than that in the past, but I understand that as it only appears with /W4 it's not a big priority.

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Wed Oct 07, 2009 12:45 pm

Re: compiler warning on vc 2008

Wed Oct 07, 2009 12:45 pm

Thanx for the answers,
For the sake of clarity:
I've added the following lines in Functors.h:

Code: Select all: ...// ei_scalar_multiple_op def private: ei_scalar_multiple_op& operator=(const ei_scalar_multiple_op&); ... ...// ei_scalar_constant_op def private: ei_scalar_constant_op& operator=(const ei_scalar_constant_op&); ...

best regards,
grinderfox

Fri Oct 09, 2009 11:15 am

Re: compiler warning on vc 2008

Fri Oct 09, 2009 11:15 am

Ok, I just started taking a look at the /W4 warnings in 2.x. Honestly, I am not going to fix them. There are so many warnings that I am amazed you found the assignment issue between all the other ones. My recommendation is to stick to /W4 or wait for the release beyond 2.x.

Cheers,
Hauke