Re: std::map<> error message only in in release mode

From:

Maxim Yegorushkin <maxim.yegorushkin@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Sun, 18 Oct 2009 00:47:12 +0100

Message-ID:

<4ada5780$0$9752$6e1ede2f@read.cnntp.org>

On 17/10/09 23:36, Rune Allnor wrote:

Hi all.

I have an application that compiles silently in debug mode. When
switching
to release mode, the following error message appears:

C:\Program Files\Microsoft Visual Studio 9.0\VC\include\xtree(1268) :
error C3848: expression having type 'const
mynamespace::pointListLess<T>' would lose some const-volatile
qualifiers in order to call 'bool
mynamespace::pointListLess<T>::operator ()(const size_t&,const size_t
&)'

It probably says that there is a const object of type
mynamespace::pointListLess<T> whose operator() is being called. Make
that operator a const functions, e.g.:

bool operator()(...) const

> I have never seen this error before, and What should I look for to
> find the cause?
> Except for one message that points out the class where the map is
> declared, the
> remaining error messages refer to the map and xtree headers.

Normally, standard containers like set<> and map<> store the comparison
functor as a member (or a base class of a member to take advantage of
empty base class optimization). Some member functions of the container
are const and in those functions the comparison functor is const. Thus
there need to be a const version of functor::operator().

--
Max