调整大型结构向量大小时出现分段错误 [英] segmentation fault on resizing a vector of large structures

问题描述

下面的代码产生了一个分段错误，我不明白为什么.下面的代码使用一个向量来存储多个大型结构体，但该代码不会运行并生成分段错误.我不明白为什么.我的理解是 vector resize 在堆中分配内存，所以这不应该是堆栈溢出问题.我的系统具有非常大的物理内存 (256 GB)，并且代码以 64 位模式编译，因此仅分配 40 MB 应该不是问题.有什么想法吗?

The code below is generating a segementation fault, and I do not understand why. The code below uses a vector to store multiple large strucutres, but the code does not run and generates a segmentation fault. I don't understand why. My understanding is that vector resize allocates memory in heap so this shouldn't be a stack overflow problem. My system has very large physical memory (256 GB) and the code is compiled in 64 bit mode so allocating just 40 MB should not be a problem. Any ideas?

非常感谢您，

#include <vector>

using namespace std;

typedef struct _tmp_t {
    int a_data[10*1000*1000];/* large array */
} tmp_t;

int main( void ) {
    vector<tmp_t> v_tmp;

    v_tmp.resize( 1 );

    return 0;
}

推荐答案

问题是调用 std::vector::resize 会创建临时对象(注意它有第二个参数默认T());这些驻留在堆栈中.所以你的筹码很严重.

The problem is that calling std::vector::resize will create temporary objects (note that it has a second argument that defaults to T()); these reside on the stack. So you're blowing your stack.

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