如何在 C++ 中初始化指向特定内存地址的指针
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How to initialize a pointer to a specific memory address in C++
提问by karlphillip
An interesting discussion about this started herebut no one have been able to provide the C++ way of doing:
一个有趣的讨论从这里开始，但没有人能够提供 C++ 的做法：
#include <stdio.h>
int main(void)
{
int* address = (int *)0x604769;
printf("Memory address is: 0x%p\n", address);
*address = 0xdead;
printf("Content of the address is: 0x%p\n", *address);
return 0;
}
What is the most appropriate way of doing such a thing in C++?
在 C++ 中做这样的事情最合适的方法是什么？
回答by Coincoin
In C++, always prefer reinterpret_castover a C-cast. It's so butt ugly that someone will immediately spot the danger.
在 C++ 中，总是reinterpret_cast比 C-cast更喜欢。它的屁股丑得让人立刻发现危险。
Example:
例子：
int* ptr = reinterpret_cast<int*>(0x12345678);
That thing hurts my eyes, and I like it.
那东西刺痛了我的眼睛，我喜欢它。
回答by Armen Tsirunyan
There is NO standard and portable way to do so. Non-portable ways may include reinterpret_cast(someIntRepresentingTheAddress).
没有标准和便携的方法可以做到这一点。不可移植的方式可能包括 reinterpret_cast(someIntRepresentingTheAddress)。
回答by Michael Goldshteyn
This will work:
这将起作用：
void *address=(void *) 0xdead; // But as mentioned, it's non-standard
address=(void *) 0xdeadbeef; // Some other address
回答by Thomas Matthews
In C++, I prefer to declare the pointers as constant pointers in a header file:
在 C++ 中，我更喜欢在头文件中将指针声明为常量指针：
volatile uint8_t * const UART_STATUS_REGISTER = (uint8_t *) 0xFFFF4000;
In the C language, this is usually implemented using a macro:
在 C 语言中，这通常使用宏来实现：
#define UART_STATUS_REGISTER ((volatile uint8_t * const) 0xFFFF4000)
In the rest of the source code, the memory address is referenced via the symbolic name.
在源代码的其余部分，内存地址是通过符号名称引用的。
回答by Dan
I would add that you can call the placement operator for new if you want an objects constructor called when assigning it at the specified address:
我要补充的是，如果您希望在指定地址分配对象时调用一个对象构造函数，则可以为 new 调用放置运算符：
int *pLoc = reinterpret_cast<int*>(0x604769);
int *address = new (pLoc) int (1234); // init to a value
This is also used for memory caching objects. Create a buffer and then assign an object to it.
这也用于内存缓存对象。创建一个缓冲区，然后为其分配一个对象。
unsigned char *pBuf = new unsigned char[sizeof(CMyObject) + alignment_size];
allign_buf(pBuf);
CMyObject *pMyObj = new (pBuf) CMyObject;
