issue with the stl and operators

[Sean Farrow]

Hi:
When compiling the folowing code under visual c++ 2005 I get he following
error:
C3848: expression having type 'const BitSetComp' would lose some
const-volatile qualifiers in order to call 'const bool BitSetComp:perator
()(const KeyType &,const KeyType &)'
This is in the file xtree on line 1174. The code causing this is:
struct BitSetComp

{

bool const operator()(const KeyType& lhs, const KeyType& rhs)

{

return lhs.to_ulong() < rhs.to_ulong();

}

};

Anyone got a clue what the issue is, and what's causing this?

What is the solution?

Cheers

Sean.

 

[Ian Collins]

Not enough info, but try:

bool operator() const (const KeyType& lhs, const KeyType& rhs)

Or if you want it to compile,

bool operator()(const KeyType& lhs, const KeyType& rhs) const

 

[Sean Farrow]

Hi:
Thanks both, compiles successfully.
Sean.

Or if you want it to compile,

bool operator()(const KeyType& lhs, const KeyType& rhs) const

 

[Fraser Ross]

"Ian Collins"

Or if you want it to compile,

bool operator()(const KeyType& lhs, const KeyType& rhs) const

Is there any reason to make one non-constant? A functor wouldn't be
adaptable if it wasn't constant.


Fraser.