我想，以适应现有的code到64位的机器。的主要问题是，在一个功能，previous codeR使用一个void *论点，即转换成合适的类型的函数本身。简单例子：

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;
        // ...
    }
}

当然，在64位机器上，我得到的错误：

Of course, on a 64 bit machine, I get the error:

error: cast from 'void*' to 'int' loses precision

我想纠正这一点，以便它仍然工作在32位机器上，并且尽可能干净。你知道吗？

I would like to correct this so that it still works on a 32 bit machine and as cleanly as possible. Any idea ?

推荐答案

为size_t'和'ptrdiff_t型的要求，以符合您的体系结构（不管它是什么）。所以，我觉得，而不是使用'廉政'，你应该能够使用'为size_t'，它在64位系统应该是一个64位的类型。

'size_t' and 'ptrdiff_t' are required to match your architecture (whatever it is). Therefore, I think rather than using 'int', you should be able to use 'size_t', which on a 64 bit system should be a 64 bit type.

此讨论 unsigned int类型VS为size_t 进入更详细一点。

This discussion unsigned int vs size_t goes into a bit more detail.