Boost C++ Libraries: Ticket #10340: No boost::promise::set_value(const T&) overload present in C++03 mode

anonymous — Mon, 11 Aug 2014 11:38:50 GMT

The error you pasted is due to a syntax error and doesn't match the code you pasted:

t.cpp: In function ‘int main()’: t.cpp:12:78: error: expected primary-expression before ‘f’
const boost::unique_future<foo>& fut = boost::make_ready_future( foo f(42) );

(Also the output would be a lot more useful with -Wno-unused-local-typedefs)

anonymous — Mon, 11 Aug 2014 11:43:29 GMT

Simpler test case:

#include <boost/thread/future.hpp>
struct foo {
  foo(int i_) { }
};
int main() {
  boost::promise<foo> p;
  const foo f(42);
  p.set_value(f);
}

This fails with -DBOOST_THREAD_USES_MOVE but compiles OK without.

rob.desbois@… — Wed, 13 Aug 2014 08:53:45 GMT

Agh, apologies for the brainfail there. Problem hopefully clear from the bug title, but for completeness here is the compile error with 1.55, g++ 4.8.2, and -DBOOST_THREAD_USES_MOVE:

In file included from t.cpp:1:0:
../deps/boost/include/boost/thread/future.hpp: In instantiation of ‘boost::unique_future<typename boost::decay<T>::type> boost::make_ready_future(const T&) [with T = foo; typename boost::decay<T>::type = foo]’:
t.cpp:14:35:   required from here
../deps/boost/include/boost/thread/future.hpp:3634:5: error: no matching function for call to ‘boost::promise<foo>::set_value(const foo&)’
     p.set_value(boost::forward<future_value_type>(value));
     ^
../deps/boost/include/boost/thread/future.hpp:3634:5: note: candidates are:
In file included from t.cpp:1:0:
../deps/boost/include/boost/thread/future.hpp:2052:14: note: void boost::promise<R>::set_value(typename boost::detail::future_traits<T>::source_reference_type) [with R = foo; typename boost::detail::future_traits<T>::source_reference_type = foo&]
         void set_value(typename detail::future_traits<R>::source_reference_type r)
              ^
../deps/boost/include/boost/thread/future.hpp:2052:14: note:   no known conversion for argument 1 from ‘const foo’ to ‘boost::detail::future_traits<foo>::source_reference_type {aka foo&}’
../deps/boost/include/boost/thread/future.hpp:2064:14: note: void boost::promise<R>::set_value(typename boost::detail::future_traits<T>::rvalue_source_type) [with R = foo; typename boost::detail::future_traits<T>::rvalue_source_type = boost::rv<foo>&]
         void set_value(typename detail::future_traits<R>::rvalue_source_type r)
              ^
../deps/boost/include/boost/thread/future.hpp:2064:14: note:   no known conversion for argument 1 from ‘const foo’ to ‘boost::detail::future_traits<foo>::rvalue_source_type {aka boost::rv<foo>&}’

viboes — Thu, 21 Aug 2014 08:03:41 GMT

IIUC you need to make foo movable in C++98 compilers.

viboes — Sun, 24 Aug 2014 23:57:27 GMT

Replying to viboes:

IIUC you need to make foo movable in C++98 compilers.

Forget this comment, please :(

description changed

viboes — Sat, 30 Aug 2014 10:05:58 GMT

description modified (diff)

description changed

viboes — Sat, 30 Aug 2014 10:06:49 GMT

description modified (diff)

viboes — Sat, 30 Aug 2014 11:46:20 GMT

Please, could you tell me if the following patch works for you

git diff ../include/boost/thread/future.hpp
diff --git a/include/boost/thread/future.hpp b/include/boost/thread/future.hpp
index 184d305..c7e81d5 100644
--- a/include/boost/thread/future.hpp
+++ b/include/boost/thread/future.hpp
@@ -553,7 +553,7 @@ namespace boost
           //typedef typename conditional<boost::is_fundamental<T>::value,T,BOOST_THREAD_RV_REF(T)>::type move_dest_type;
           typedef T move_dest_type;
 #elif defined BOOST_THREAD_USES_MOVE
-          typedef typename conditional<boost::is_fundamental<T>::value,T,T&>::type source_reference_type;
+          typedef typename conditional<boost::is_fundamental<T>::value,T,T const&>::type source_reference_type;
           //typedef typename conditional<boost::is_fundamental<T>::value,T,BOOST_THREAD_RV_REF(T)>::type rvalue_source_type;
           //typedef typename conditional<boost::enable_move_utility_emulation<T>::value,BOOST_THREAD_RV_REF(T),T>::type move_dest_type;
           typedef BOOST_THREAD_RV_REF(T) rvalue_source_type;

milestone changed

viboes — Sat, 30 Aug 2014 16:00:32 GMT

milestone To Be Determined → Boost 1.57.0

https://github.com/boostorg/thread/commit/0543b522cb6c2af197a82dea48805ea19be6f4f7

rob.desbois@… — Thu, 04 Sep 2014 12:34:02 GMT

It does indeed; thanks viboes.

owner, status changed

viboes — Fri, 05 Sep 2014 06:08:23 GMT

owner changed from Anthony Williams to viboes
status new → assigned

status changed; resolution set

viboes — Tue, 16 Sep 2014 06:14:57 GMT

status assigned → closed
resolution → fixed