C++ - Get value of a particular memory address

c++ pointers memory dereference memory-address
Zyyk Savvins picture Zyyk Savvins · Sep 6, 2012 · Viewed 31.3k times · Source

I was wondering whether it is possible to do something like this:

unsigned int address = 0x0001FBDC; // Random address :P
int value = *address; // Dereference of address

Meaning, is it possible to get the value of a particular address in memory ?

Thanks

Answer

Kerrek SB picture Kerrek SB · Sep 6, 2012

You can and should write it like this:

#include <cstdint>

uintptr_t p = 0x0001FBDC;
int value = *reinterpret_cast<int *>(p);

Note that unless there is some guarantee that p points to an integer, this is undefined behaviour. A standard operating system will kill your process if you try to access an address that it didn't expect you to address. However, this may be a common pattern in free-standing programs.

(Earlier versions of C++ should say #include <stdint.h> and intptr_t.)

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