Boost coroutine不会编译，因为对callcc的调用不明确

Question

我试图在工作中的C++项目中使用协同机制。但是，由于对callcc()的使用不明确，它将不会编译。我尝试在coroutine构造函数中指定分配器，但这似乎没有什么区别。

在将代码剥离到其最基本的基本要素之后，我以非常类似于boost文档中的fibbonacci示例来重现这个问题。

#include <iostream>
#include <boost/coroutine2/all.hpp>

/*
    c++ -std=c++11 -o corofib corofib.cpp
*/

typedef boost::coroutines2::coroutine<unsigned long> coro_t;

coro_t::pull_type generator(
    [](coro_t::push_type& sink) {
        unsigned long first = 1L;
        unsigned long second = 1L;
        unsigned long answer;

        sink(first);
        sink(second);
        while(1) {
            answer = first + second;
            first = second;
            second = answer;
            sink(answer);
        };
    }
);


int main(int argc, char* argv[]) {
    generator();
    std::cout << generator.get() << std::endl;
    generator();
    std::cout << generator.get() << std::endl;
    generator();
    std::cout << generator.get() << std::endl;
    generator();
    std::cout << generator.get() << std::endl;
}

我正在使用：

• Boost 1.64
• gcc版4.9.2
• Linux委托3.16.0-4-AMD 64 #1 SMP Debian 3.16.39-1+GNU 8u 2 (2017-03-07) x86_64 GNU/Linux

这是我收到的错误信息。为了缩短这篇文章，我删除了“必需的”通知：

lear@delegato:~/lamu$ c++ -std=c++14 -o corofib corofib.cpp
In file included from /usr/local/include/boost/coroutine2/detail/coroutine.hpp:48:0,
                 from /usr/local/include/boost/coroutine2/coroutine.hpp:15,
                 from /usr/local/include/boost/coroutine2/all.hpp:10,
                 from corofib.cpp:2:
/usr/local/include/boost/coroutine2/detail/pull_control_block_cc.ipp: In instantiation of ‘boost::coroutines2::detail::pull_coroutine<T>::control_block::control_block(boost::context::preallocated, StackAllocator, Fn&&) [with StackAllocator = boost::context::basic_fixedsize_stack<boost::context::stack_traits>; Fn = <lambda(boost::coroutines2::coroutine<long unsigned int>::push_type&)>; T = long unsigned int]’:
/usr/local/include/boost/coroutine2/detail/pull_control_block_cc.ipp:105:14: error: call of overloaded ‘callcc(const std::allocator_arg_t&, boost::context::preallocated&, boost::context::basic_fixedsize_stack<boost::context::stack_traits>&, boost::coroutines2::detail::pull_coroutine<T>::control_block::control_block(boost::context::preallocated, StackAllocator, Fn&&) [with StackAllocator = boost::context::basic_fixedsize_stack<boost::context::stack_traits>; Fn = <lambda(boost::coroutines2::coroutine<long unsigned int>::push_type&)>; T = long unsigned int]::<lambda(boost::context::continuation&&)>)’ is ambiguous
             });
              ^
/usr/local/include/boost/coroutine2/detail/pull_control_block_cc.ipp:105:14: note: candidates are:
In file included from /usr/local/include/boost/coroutine2/detail/pull_control_block_cc.hpp:14:0,
                 from /usr/local/include/boost/coroutine2/detail/coroutine.hpp:37,
                 from /usr/local/include/boost/coroutine2/coroutine.hpp:15,
                 from /usr/local/include/boost/coroutine2/all.hpp:10,
                 from corofib.cpp:2:
/usr/local/include/boost/context/continuation.hpp:469:1: note: boost::context::continuation boost::context::callcc(std::allocator_arg_t, StackAlloc, Fn&&, Arg ...) [with StackAlloc = boost::context::preallocated; Fn = boost::context::basic_fixedsize_stack<boost::context::stack_traits>&; Arg = {boost::coroutines2::detail::pull_coroutine<T>::control_block::control_block(boost::context::preallocated, StackAllocator, Fn&&) [with StackAllocator = boost::context::basic_fixedsize_stack<boost::context::stack_traits>; Fn = <lambda(boost::coroutines2::coroutine<long unsigned int>::push_type&)>; T = long unsigned int]::<lambda(boost::context::continuation&&)>}]
 callcc( std::allocator_arg_t, StackAlloc salloc, Fn && fn, Arg ... arg) {
 ^
/usr/local/include/boost/context/continuation.hpp:483:1: note: boost::context::continuation boost::context::callcc(std::allocator_arg_t, boost::context::preallocated, StackAlloc, Fn&&, Arg ...) [with StackAlloc = boost::context::basic_fixedsize_stack<boost::context::stack_traits>; Fn = boost::coroutines2::detail::pull_coroutine<T>::control_block::control_block(boost::context::preallocated, StackAllocator, Fn&&) [with StackAllocator = boost::context::basic_fixedsize_stack<boost::context::stack_traits>; Fn = <lambda(boost::coroutines2::coroutine<long unsigned int>::push_type&)>; T = long unsigned int]::<lambda(boost::context::continuation&&)>; Arg = {}]
 callcc( std::allocator_arg_t, preallocated palloc, StackAlloc salloc, Fn && fn, Arg ... arg) {
 ^
/usr/local/include/boost/context/continuation.hpp:514:1: note: boost::context::continuation boost::context::callcc(std::allocator_arg_t, boost::context::preallocated, StackAlloc, Fn&&) [with StackAlloc = boost::context::basic_fixedsize_stack<boost::context::stack_traits>; Fn = boost::coroutines2::detail::pull_coroutine<T>::control_block::control_block(boost::context::preallocated, StackAllocator, Fn&&) [with StackAllocator = boost::context::basic_fixedsize_stack<boost::context::stack_traits>; Fn = <lambda(boost::coroutines2::coroutine<long unsigned int>::push_type&)>; T = long unsigned int]::<lambda(boost::context::continuation&&)>]
 callcc( std::allocator_arg_t, preallocated palloc, StackAlloc salloc, Fn && fn) {
 ^
/usr/local/include/boost/context/continuation.hpp:457:1: note: boost::context::continuation boost::context::callcc(Fn&&, Arg ...) [with Fn = const std::allocator_arg_t&; Arg = {boost::context::preallocated, boost::context::basic_fixedsize_stack<boost::context::stack_traits>, boost::coroutines2::detail::pull_coroutine<T>::control_block::control_block(boost::context::preallocated, StackAllocator, Fn&&) [with StackAllocator = boost::context::basic_fixedsize_stack<boost::context::stack_traits>; Fn = <lambda(boost::coroutines2::coroutine<long unsigned int>::push_type&)>; T = long unsigned int]::<lambda(boost::context::continuation&&)>}; <template-parameter-1-3> = void]
 callcc( Fn && fn, Arg ... arg) {

我认为代码基本上是正确的:我只需要在某种程度上对此进行模糊处理。

我可以说在蟒蛇身上做这件事是多么容易，但这可能会引起笑声。

Answer 1

这是Boost.Context中的一个bug，它位于已报告和固定上游。您可以找到专门针对Boost 1.64 这里的修补程序。