2011/6/27 John M. Dlugosz :

I brought this up a while back, and I ran into it again yesterday.  Using boost::format to produce a string, as opposed to sending it directly to cout, is awkward.

   boost::format ("blah blah blah") % exp1 % exp2 %exp3

is fine in and of itself.  But then what?  You need to wrap the whole thing in extra parens to use str:

   std::string s= (boost::format ("blah blah blah") % exp1 % exp2 %exp3).str();

WHY NOT allow implicit conversion to string?

Or, some other mechanism that doesn't complicate the expression and bury the interesting part?

use str() free function: std::string s = str(boost::format ("blah blah blah") % exp1 % exp2 %exp3) same when passing format to functions taking std::string params Szymon