[Boost-users] filesystem lambda and for_each

Subject: [Boost-users] filesystem lambda and for_each
From: Jean-Christophe Roux (jcxxr_at_[hidden])
Date: 2010-08-19 14:43:57

hello,

Despite some research, I am struggling to combine boost filesystem, boost lambda 
and STL for_each.

 32   std::string str = "";
 33   std::string path = "/tmp";
 34   boost::filesystem::directory_iterator it(path);
 35   while(it != boost::filesystem::directory_iterator())
 36   {
 37     str += it->path().filename() + "<br>";
 38     ++it;
 39   }

works fine
but
 40   std::for_each(boost::filesystem::directory_iterator(path), 
boost::filesystem::directory_iterator(),  
 41                 str += *boost::lambda::_1.path().parent_path() );
does not compile with the error message that :
 error: ‘const struct 
boost::lambda::lambda_functor<boost::lambda::placeholder<1> >’ has no member 
named ‘path’
I don't understand why and I don't really see how I could have this work.

Also, I am wondering why with 
_1 
instead of 
boost::lambda::_1
 I am getting:
error: reference to ‘_1’ is ambiguous 
/usr/local/include/boost/lambda/core.hpp:69: 

thanks!