On Tue, Feb 3, 2009 at 9:45 AM, Igor R wrote:

The following code crashes in for_each when trying to output the 1st pair. What's wrong with it?

Thanks!

namespace bl = boost::lambda; std::map temp; temp["a"] = "1"; temp["b"] = "2"; const std::map attrs(temp); typedef std::pair string_pair; std::stringstream stream; std::for_each(attrs.begin(), attrs.end(), stream << bl::bind(&string_pair::first, bl::_1) << bl::bind(&string_pair::second, bl::_1));

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What's the problem? This works for me - full source follows. #include "boost/lambda/lambda.hpp" #include "boost/lambda/bind.hpp" #include <algorithm> #include <map> #include <iostream> #include <sstream> int main( ) { namespace bl = boost::lambda; std::map temp; temp["a"] = "1"; temp["b"] = "2"; const std::map attrs(temp); typedef std::pair string_pair; std::stringstream stream; std::for_each(attrs.begin(), attrs.end(), stream << bl::bind(&string_pair::first, bl::_1) << bl::bind(&string_pair::second, bl::_1)); } Using Visual Studio 2005 & Boost 1.36 Rob. --

On Tue, Feb 3, 2009 at 9:45 AM, Igor R wrote:

The following code crashes in for_each when trying to output the 1st pair. What's wrong with it?

Thanks!

namespace bl = boost::lambda; std::map temp; temp["a"] = "1"; temp["b"] = "2"; const std::map attrs(temp); typedef std::pair string_pair; std::stringstream stream; std::for_each(attrs.begin(), attrs.end(), stream << bl::bind(&string_pair::first, bl::_1) << bl::bind(&string_pair::second, bl::_1));

Try changing the string_pair typedef to: std::pair string_pair; Not 100% sure *why* this makes it run rather than crash (with VC++ 2008, Boost 1.37.0), but it makes some sort of sense, as the key in a map is immutable. Stuart Dootson

On Tue, Feb 3, 2009 at 9:45 AM, Igor R wrote:

The following code crashes in for_each when trying to output the 1st pair. What's wrong with it?

Thanks!

namespace bl = boost::lambda; std::map temp; temp["a"] = "1"; temp["b"] = "2"; const std::map attrs(temp); typedef std::pair string_pair; std::stringstream stream; std::for_each(attrs.begin(), attrs.end(), stream << bl::bind(&string_pair::first, bl::_1) << bl::bind(&string_pair::second, bl::_1));

Or essentially the same solution, but tidied up

#include "boost/lambda/lambda.hpp" #include "boost/lambda/bind.hpp" #include <algorithm> #include <map> #include <iostream> #include <sstream> int main( ) { namespace bl = boost::lambda; typedef std::map map_type; map_type temp; temp["a"] = "1"; temp["b"] = "2"; const map_type attrs(temp); typedef map_type :: value_type string_pair; std::stringstream stream; std::for_each(attrs.begin(), attrs.end(), stream << bl::bind(&string_pair::first, bl::_1) << bl::bind(&string_pair::second, bl::_1)); } Cheers, Rob.