boost :: bind（）是按引用还是按值复制参数？ [英] Does boost::bind() copy parameters by reference or by value?

问题描述

为什么valgrind的DRD工具会抱怨线程加载冲突...大小为4：关于这样的代码：

Why does valgrind's DRD tool complaines "Conflicting load by thread ... at size 4": about such code:

void SomeFunction(const int& value)
{
    boost::bind(..., value); /* <-- complaines on this line
                                with last backtrace function "new(int)" */
}

boost :: bind（）是否按引用或值存储值？

Does boost::bind() stores values by reference or value?

推荐答案

值。 1

但是您可以将其做成由ref复制：

void SomeFunction(const int& value)
{
    boost::bind(..., boost::ref(value)); 
    boost::bind(..., boost::cref(value)); // by const ref
}

1 http://www.boost.org/doc/libs/1_46_1/libs/bind/bind.html#Purpose

i值的副本存储在函数对象中。 boost :: ref和boost :: cref可用于使函数对象存储对对象的引用，而不是副本：
int i = 5;

a copy of the value of i is stored into the function object. boost::ref and boost::cref can be used to make the function object store a reference to an object, rather than a copy: int i = 5;

bind（f，ref（i），_1）;

bind(f, ref(i), _1);

bind（f，cref（42），_1）;

bind(f, cref(42), _1);

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