[Boost-users] Using Boost bind to replace an uary_function

From: yinglcs2_at_[hidden]
Date: 2006-02-15 13:42:57

I have code which calls unary_function with the
count_if() algorithm.  Like this:

class do_hasContainerBlock : public
unary_function<BlockData*, bool>
{
public:
bool operator() (BlockData* bd) {
  return bd->isContainer();   
 }
};

bool hasContainerBlock(list<BlockData*>& bdl) {
        
int count = count_if (bdl.begin(), bdl.end(),
do_hasContainerBlock());
return (count > 0);
}
And I would like to replace the unary function with
boost bind library, like this:
int count = count_if (bdl.begin(), bdl.end(), 
bind( &BlockData::isContainer, _1) );

But this code does not copmile,I get this error:
g++ -O0 -g3 -Wall -c -fmessage-length=0
-oBlockDataUtils.o ../BlockDataUtils.cpp
../BlockDataUtils.cpp: In function ‘bool
hasContainerBlock(BlockDataList&)’:
../BlockDataUtils.cpp:95: error: no matching function
for call to ‘bind(<unknown type>, const
boost::lambda::lambda_functor<boost::lambda::placeholder<1>
>&)’

Can you please tell me how to fix that?

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com