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From: David Brownell (brownell_at_[hidden])
Date: 2001-10-22 13:14:35
Excellent, the first option will work in this situation. Thanks for all the
help!
-----Original Message-----
From: Peter Dimov [mailto:pdimov_at_[hidden]]
Sent: Monday, October 22, 2001 11:23 AM
To: boost_at_[hidden]
Subject: Re: [boost] bind, template functions, and the linker
From: <brownell_at_[hidden]>
> I don't think this is a problem with bind, but more of a C++ issue, so
> my apologies if this is a bit off topic. I am passing a template
> function to bind, and the resulting "bound" function is used as the
> UnaryFunction in std::for_each. When I compile this application,
> everything works as expected, but when the linker does its thing, it
> can't find the template function.
[...]
I assume you are using MSVC.
> std::for_each(v.begin(), v.end(), boost::bind
> (TemplateFunction<unsigned long>, _1));
I was able to get around the problem by using:
bool (*pf) (unsigned long &) = &TemplateFunction<unsigned long>;
std::for_each(v.begin(), v.end(), boost::bind(pf, _1));
This is a good idea in general since "TemplateFunction<unsigned long>" is
not guaranteed to be valid by itself (there is a defect report against
this.)
Another option is to turn the function into a function object:
template<class T> struct F
{
bool operator()(T & t)
{
t = 2;
return true;
}
};
and then
std::for_each(v.begin(), v.end(), boost::bind<bool>(F<unsigned long>(),
_1));
A third option is to use a fancier function object:
struct F
{
template<class T> bool operator()(T & t)
{
t = 2;
return true;
}
};
and, correspondingly,
std::for_each(v.begin(), v.end(), boost::bind<bool>(F(), _1));
Hope this helps. :-)
-- Peter Dimov Multi Media Ltd. Info: http://www.boost.org Unsubscribe: <mailto:boost-unsubscribe_at_[hidden]> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
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