Converting a pointer into an integer
32-bit, 64-bit, c++, casting, gcc
Solution
Use `intptr_t` and `uintptr_t`.
To ensure it is defined in a portable way, you can use code like this:
#if defined(__BORLANDC__)
typedef unsigned char uint8_t;
typedef __int64 int64_t;
typedef unsigned long uintptr_t;
#elif defined(_MSC_VER)
typedef unsigned char uint8_t;
typedef __int64 int64_t;
#else
#include <stdint.h>
#endif
Just place that in some .h file and include wherever you need it.
Alternatively, you can download Microsoft’s version of the `stdint.h` file from here or use a portable one from here.
Problem
I am trying to adapt an existing code to a 64 bit machine. The main problem is that in one function, the previous coder uses a void* argument that is converted into suitable type in the function itself. A short example: ``` void function(MESSAGE_ID id, void* param) { if(id == FOO) { int real_param = (int)param; // ... } } ``` Of course, on a 64 bit machine, I get the error: ``` error: cast from 'void*' to 'int' loses precision ``` I would like to correct this so that it still works on a 32 bit machine and as cleanly as possible. Any idea ?