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增强融合:一个奇怪的问题取决于矢量上元素的数量

boost-fusion vector boost c++

2

chaos.ct · 技术社区 · 16 年前

我正在尝试在个人项目中使用Boost::Fusion(Boost v1.42.0)。这段代码有一个有趣的错误:

#include "boost/fusion/include/sequence.hpp"
#include "boost/fusion/include/make_vector.hpp"
#include "boost/fusion/include/insert.hpp"
#include "boost/fusion/include/invoke_procedure.hpp"
#include "boost/fusion/include/make_vector.hpp"
#include <iostream>

class Class1
{ 
    public:
    typedef boost::fusion::vector<int,float,float,char,int,int> SequenceType;
    SequenceType s;
        Class1(SequenceType v):s(v){}
};

class Class2
{
    public:
    Class2(){}
    void met(int a,float b ,float c ,char d ,int e,int f)
    {
        std::cout << a << " " << b << " " << c << " " << d << " " << e << std::endl;
    }
};

int main(int argn, char**)
{
Class2 p;
Class1 t(boost::fusion::make_vector(9,7.66f,8.99f,'s',7,6));
boost::fusion::begin(t.s); //OK
boost::fusion::insert(t.s, boost::fusion::begin(t.s), &p); //OK
boost::fusion::invoke_procedure(&Class2::met,boost::fusion::insert(t.s, boost::fusion::begin(t.s), &p)); //FAILS
}

未能编译(GCC 4.4.1):

In file included from /home/thechaos/Escriptori/of_preRelease_v0061_linux_FAT/addons/ofxTableGestures/ext/boost/fusion/include/invoke_procedur
e.hpp:10,
                 from problema concepte.cpp:11:
/home/thechaos/Escriptori/of_preRelease_v0061_linux_FAT/addons/ofxTableGestures/ext/boost/fusion/functional/invocation/invoke_procedure.hpp: I
n function âvoid boost::fusion::invoke_procedure(Function, const Sequence&) [with Function = void (Class2::*)(int, float, float, char, int, in
t), Sequence = boost::fusion::joint_view<boost::fusion::joint_view<boost::fusion::iterator_range<boost::fusion::vector_iterator<const boost::f
usion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_>, 0>, 
boost::fusion::vector_iterator<boost::fusion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fus
ion::void_, boost::fusion::void_>, 0> >, const boost::fusion::single_view<Class2*> >, boost::fusion::iterator_range<boost::fusion::vector_iter
ator<boost::fusion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion:
:void_>, 0>, boost::fusion::vector_iterator<const boost::fusion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion
::void_, boost::fusion::void_, boost::fusion::void_>, 6> > >]â:
problema concepte.cpp:39:   instantiated from here
/home/thechaos/Escriptori/of_preRelease_v0061_linux_FAT/addons/ofxTableGestures/ext/boost/fusion/functional/invocation/invoke_procedure.hpp:88
: error: incomplete type âboost::fusion::detail::invoke_procedure_impl<void (Class2::*)(int, float, float, char, int, int), const boost::fusio
n::joint_view<boost::fusion::joint_view<boost::fusion::iterator_range<boost::fusion::vector_iterator<const boost::fusion::vector<int, float, f
loat, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_>, 0>, boost::fusion::vector_itera
tor<boost::fusion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::
void_>, 0> >, const boost::fusion::single_view<Class2*> >, boost::fusion::iterator_range<boost::fusion::vector_iterator<boost::fusion::vector<
int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_>, 0>, boost::fusion:
:vector_iterator<const boost::fusion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::voi
d_, boost::fusion::void_>, 6> > >, 7, true, false>â used in nested name specifier

但是,如果我将向量中的参数个数和方法从6改为5, int,float,float,char,int,int 到 int,float,float,char,int ,我可以毫无问题地编译它。

我怀疑最大数量的参数是一个限制,但我试图通过定义 FUSION_MAX_VECTOR_SIZE 没有成功。

我看不出我做错了什么。你能复制这个吗?它会是一个增强型错误吗(我怀疑,但这不是不可能的)?

1 回复 | 直到 14 年前

1

3

GManNickG 16 年前

是的,确实需要更改一些迭代限制。你换错了。:)

你需要定义的是 BOOST_FUSION_INVOKE_PROCEDURE_MAX_ARITY ;默认为6。您显然需要7个(但也可以将其增加到10个):

#define BOOST_FUSION_INVOKE_PROCEDURE_MAX_ARITY 10

#include "boost/fusion/include/sequence.hpp"
#include "boost/fusion/include/make_vector.hpp"
#include "boost/fusion/include/insert.hpp"
#include "boost/fusion/include/invoke_procedure.hpp"
#include "boost/fusion/include/make_vector.hpp"
#include <iostream>
.
.
.

有 three total 在调用域中。

每当你在寻找某物的极限时,搜索 documentation . 选择一个与你所做的相关的。从那里,它告诉您默认值和选项是什么。

就代码本身而言,我应该指出 push_front 功能:

#include "boost/fusion/include/push_front.hpp"

// ...

boost::fusion::invoke_procedure(&Class2::met,
                                boost::fusion::push_front(t.s, &p));

所以您不需要在开始时进行更详细的插入。