How to make the heap address(by new) have the same every time the program runs?

[User 13049321]

char* str = new char[128];

At first run, the address of str is 0x12345678, and second run, the address of str is 0x00123456, I want the address of str constant, not change every time run. I wish: At first run, the address of str is 0x12345678, and second run, the address of str is 0x12345678, every time run, the address of str is 0x12345678.

[k5054]

There's no mechanism within C++ to do that. In fact, modern run time systems are designed so that program data spaces are different for each program invocation. For example:

$ cat example.c
\#include

int main()
{
int n;
printf("&n = %p\n" , &n);
}
$ for ((i=0;i<4;++i)); do ./example; done
&n = 0x7fff2ddda67c
&n = 0x7ffdece1243c
&n = 0x7ffe42e7d2bc
&n = 0x7fffd2e78b2c
$

Note that even this simple program gives different addresses for the address of int n on successive runs. This is to make it difficult for any malicious program to interfere with and modify a running program, or to predict where a program will place data. Also note that in any modern OS (outside of some embeded applications), you are dealing with virtual addresses anyway, so where your process thinks an object is and where the object actually is in physical memory are completely different, so you need to know things like the value page frames and things to work out a physical address of an object in memory. Outside of some sort of educational value, I can't see any up side to always getting the same address when calling new, so maybe you might want to think about why you want this behavior and come up with a new plan.

[CPallini]

You could mimic that implementing you own memory manager and then globally replacing the default new operator.

[David Crow]

Are you referring to either the /base or /fixed linker option?

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[leon de boer]

The question is stupid, there is no way a dynamic heap manager can guarantee it wont give the memory space away to some other call for memory allocation. To do what you asked it would have to keep the memory "available" anyhow, so for the love of all things coding just declare the thing static in that case (unless you actually want a global). My C++ is rusty with string objects but it should be something like

static char* str = char[128];

In C it is simpler

static char str[128];

Problem solved it now has the same address everytime locally, and effectively does the same thing that any crazy heap manager doing what you asked would have to do. I am assuming you are going to change the string at times, so you want a variable not a constant.

In vino veritas

[Lost User]

The first form is not valid C++. And the second form still does not work since the compiler and the linker can allocate that array in different places. As you so rightly say, the question is stupid.

[User 13049321]

Thanks

[User 13049321]

Thanks

[User 13049321]

First, I use Visual Studio. Invalid after adding add "/fixed" linker option. and error LNK1146: no argument specified with option '/base'