C结构实例覆盖以前的实例

我是C语言的新手，所以答案可能很明显，但我就是想不通

我正在努力创造。我使用Windows EnumWindows函数在所有窗口中循环。在回调函数中，我为每个窗口创建windowHandle-structure的新实例。然而，出于某种原因，它似乎不会创建新实例，而只是覆盖旧实例。或者它会创建新实例，但当我给属性windowHandle->title赋值时，它会将更改应用到windowHandle的每个实例吗

回调函数：

BOOL CALLBACK delegate(HWND wnd, LPARAM param){
if (filter(wnd)){ //<- just to make sure it's kind of window that we want.
            char windowName[256] = {};
            GetWindowText(wnd, windowName, sizeof(windowName));
            windowHandle *handle = malloc(sizeof(windowHandle)); //<- create new instance of windowHandle for each window
            handle->hWND = wnd;
            handle->title = windowName;
            insert((windowArray*) param, handle); //<- insert each windowHandle in our 'vector'
        }
// but return true here so that we iterate all windows
return TRUE;
}

windowArray* array = array_init(20);
EnumWindows(&delegate, (LPARAM) array); //<- not quite sure what that '&'-sign does?

最后插入：

int insert(windowArray* array, void* handle){
    int index = (array->count * array->objectSize);
    if(index > 0){
        printf("\n%s %s\n", "first element's title is: ", array->windows->title); //<- prints to see if new handle overwrite the previous ones
    }
    printf("%s %s %s %p %s %d\n", "Inserted element ", ((windowHandle*)handle)->title, " with pointer ", handle, " on index ", index);
    fflush(stdout); //<- prints info about first & current window
    memcpy(array->windows + (index), (windowHandle*)handle, array->objectSize);
    array->count++;
}

然后，如果我打印windowArray->windows的全部内容，我会得到以下结果：

Getting value  src , at index  0  and pointer  0000000000FBBB80
Getting value  src , at index  16  and pointer  0000000000FBBC80
Getting value  src , at index  32  and pointer  0000000000FBBD80
Getting value  src , at index  48  and pointer  0000000000FBBE80
Getting value  src , at index  64  and pointer  0000000000FBBF80
Getting value  src , at index  80  and pointer  0000000000FBC080
Getting value  src , at index  96  and pointer  0000000000FBC180

---

另外，我还想知道为什么windowArray的

windows

-属性的指针不同于在委托中创建的

*handle

-对象的指针？这似乎不是很有效的记忆方式？

您将

handle->title

设置为指向

windowName

。但一旦退出此作用域，

windowName

将不再存在。因此，您的结构包含一个指向不再存在的数组的指针

        char windowName[256] = {};
        GetWindowText(wnd, windowName, sizeof(windowName));
        windowHandle *handle = malloc(sizeof(windowHandle)); //<- create new instance of windowHandle for each window
        handle->hWND = wnd;
        handle->title = windowName;
    }
    // when we get here, windowName ceases to exist
    // so why did we store a pointer to it?

charwindowname[256]={}；
GetWindowText（wnd、windowName、sizeof（windowName））；
windowHandle*handle=malloc（sizeof（windowHandle））//hWND=wnd；
句柄->标题=窗口名；
}
//当我们到达这里时，windowName就不存在了
//那么我们为什么要存储指向它的指针呢？

---

退出作用域后，跟随

title

指针是一个错误，因为它不再指向任何仍然活动的对象。也许将

标题

从

char*

更改为

char[256]

Ohh，这是有意义的。非常感谢。拯救了这一天。

Getting value  src , at index  0  and pointer  0000000000FBBB80
Getting value  src , at index  16  and pointer  0000000000FBBC80
Getting value  src , at index  32  and pointer  0000000000FBBD80
Getting value  src , at index  48  and pointer  0000000000FBBE80
Getting value  src , at index  64  and pointer  0000000000FBBF80
Getting value  src , at index  80  and pointer  0000000000FBC080
Getting value  src , at index  96  and pointer  0000000000FBC180

        char windowName[256] = {};
        GetWindowText(wnd, windowName, sizeof(windowName));
        windowHandle *handle = malloc(sizeof(windowHandle)); //<- create new instance of windowHandle for each window
        handle->hWND = wnd;
        handle->title = windowName;
    }
    // when we get here, windowName ceases to exist
    // so why did we store a pointer to it?