Re: [Boost-users] A question on overloaded function? Can anyone with kindness help me?

5 Jul 2009

      According to your suggestion,I tried to write:
 bind(static_castIIPrimemap::iterator,bool
                              (*)(const IIPrimemap::value_type&)>
                              (IIPrimemap::insert),
                              bind(&make_pair,_1,constant(1)));
where
typedef std::map IIPrimemap;
IIPrimemap primemapvec;

but the complier told me that:
 invalid static_cast from type `<unknown type>' to type `
   std::pair, std::pair&, std::pair*>, bool> (*)(const std::pair&)'
Can you tell me why?
 Thanks.

在2009-07-02，"Steven Watanabe"  写道：
...
AMDG
fmingu wrote:
...
Sorry for my unclearness. But how can I write the line:
bind(&std::pow,constant(-1.0),bind(&IIPrimemap::size,var(primemapvec)));
correctly and thus the program can be complied.
If not so the program can not be complied by Dev-C++ and I am confused about that.
I really want to know how to write the line correctly.
Please give me an example.
As I have said, you need to cast &std::pow to a specific
type of function pointer to resolve the ambiguity.
I'll break this down further.
a) You need to cast. I assume that you know how
casts in C++ work. If not, look up static_cast
in your favorite elementary C++ text.
b) You need to know the function pointer type to cast to.
Do you know what a function pointer type looks like?
It's similar to a function declaration.
<return type> (*)(<argument types>)
for example, given the declaration
int foo(char);
the type of &foo is int(*)(char).
Since there are several overloads of std::pow,
you need to pick the one that is most appropriate.
In Christ,
Steven Watanabe