RE: [Boost-users] Re: Bug in boost::lambda using operator <<?
On Friday, February 04, 2005 5:47 PM Kevin Wheatley wrote:
Richard_Cox@Dell.com wrote:
The program below outputs
String: <First string> Second string> Fourth string> Fifth string>
All but the first "<" is missing. Any ideas? std::for_each(coll.begin(), coll.end(), out << gt << _1
<< L"> ");
does this work?
std::for_each(coll.begin(), coll.end(), out << var(gt) << _1 << L"> ");
not sure of the fix, but out << gt associates left to right and is evaluated once and has the type of out, you want it lazy evaluated so that the whole of the expression is considered as one... see the delaying constants and variables section of the lambda documents.
Kevin
Of course, "obvious" now :-( out << gt would evaluate returning the wostream which the lambda expression created from the 2nd and 3rd <<'s then operates on. Many thanks. Richard All opinions are mine and do not represent in any way the position of Dell Corporation.
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Richard_Cox@Dell.com