silent MSVC warnings on libdns++

[fdupont]

I'll collect MSVC warnings in VS2005/2008/2010 and try to address them.
Some are spurious (as a warning for {} while(0) in macros) and should be avoided
with a pragma, some are real (mainly incompatible integer operations) and should
be fixed (for instance by a cast). As far as I know none is critical so
I put this ticket in enhancements.
Note at least a common one is related to C++: VS2010 complains about missing and
impossible to generate copy operation in class definition...

[fdupont]

log of Release (W3) build by Visual Studio 2008

[fdupont]

log of Debug (W4) build by Visual Studio 2008

[fdupont]

log of Release (W3) build by Visual Stdio 2010

[fdupont]

log of Debug (W4) build by Visual Studio 2010

[fdupont]

The exact MSVC issue is:

Compiler Warning (level 4) C4512

'class' : assignment operator could not be generated

The compiler cannot generate an assignment operator for the given class. No assignment operator was created.

An assignment operator for the base class that is not accessible by the derived class can cause this warning.

To avoid this warning, specify a user-defined assignment operator for the class.

The compiler will also generate an assignment operator function for a class that does not define one. This assignment operator is a memberwise copy of the data members of an object. Because const data items cannot be modified after initialization, if the class contains a const item, the default assignment operator would not work. Another cause of the C4512 warning is a declaration of a nonstatic data member of reference type.

You can resolve the C4512 warning for your code in one of three ways:

• Explicitly define an assignment operator for the class.
• Remove const or the reference operator from the data item in the class.
• Use the #pragma warning statement to suppress the warning.

=> I suggest the first one, BTW boost has many such definitions to avoid this particular warning.

[fdupont]

BTW this was mostly done in the last trac826 branch versions and not for libdns++ only, at the exception of missing integer casts (I fixed only trivial for iteration variable).

[tomek]

If this ticket is no longer applicable or useful, feel free to close it.