这些 valgrind/GNU 调试器错误消息是什么意思？

Question

我的程序正确终止，并且根据 Valgrind 的说法，没有内存泄漏。

但是当对象方法第一次运行时会出现以下消息。

Use of uninitialised value of size 8

获取有关上述产量的更多详细信息

==18787== Use of uninitialised value of size 8
==18787==    at 0x4017F3: Grid::init(int) (grid.cc:90)
==18787==    by 0x401D2A: main (main.cc:43)
==18787==  Uninitialised value was created by a stack allocation
==18787==    at 0x401BE4: main (main.cc:11)

我还看到以下消息：

Conditional jump or move depends on uninitialised value(s)
Invalid free() / delete / delete[] / realloc()
Address 0x7ff000b08 is on thread 1's stack

这里是 Grid::init 的代码

void Grid::init(int n){
    if (!(&(this->theGrid))) { this->clearGrid(); } //If non-empty, destroys grid

    this->theGrid = new Cell*[n]; //Create new grid of size n x n
    this->td = new TextDisplay(n); //new Text Display 
    for (int i = 0; i < n; i++){
        this->theGrid[i] = new Cell[n];
        for(int j = 0; j < n; j++){ //Cell initializations
            (this->theGrid[i][j]).setDisplay(this->td); //set display
            (this->theGrid[i][j]).setCoords(i, j); //set co-ordinates
            (this->theGrid[i][j]).setState(0); //default state
        }
    }
}

Answer 1

我猜你的代码看起来像：

条件跳转或移动取决于未初始化的值：

bool value /* nothing */;
if (value) {
}

无效的免费：

char* buf = new char[10000];
buf = &x;
delete [] buf;

既然您发布了代码，我假设第 90 行是这一行：

if (!(&(this->theGrid))) { this->clearGrid(); } //If non-empty, destroys grid

问题是您没有在构造函数中将theGrid 初始化为nullptr，然后您最终可能会得到delete[]-ing 非new[]-ed 数组。此外，如果您这样做，该代码会读起来更清晰：

if (!theGrid) {
    clearGrid();
}

你不需要到处都有this->。而且我不明白你为什么要使用theGrid的地址。