在OSX上以编程方式确定物理内存大小
我们试图找出在运行Mac OS X的计算机中安装了多少物理内存.我们找到了BSD函数sysctl().问题在于此函数要返回32位值，但是某些Mac能够寻址最大32 GB的地址，而该GB不能容纳32位值. (实际上，甚至4 GB也无法容纳32位值.)OS X(10.4或更高版本)上是否有其他API可以提供此信息?
We're trying to find out how much physical memory is installed in a machine running Mac OS X. We've found the BSD function sysctl(). The problem is this function wants to return a 32 bit value but some Macs are able to address up to 32 GB which will not fit in a 32 bit value. (Actually even 4 GB won't fit in a 32 bit value.) Is there another API available on OS X (10.4 or later) that will give us this info?
答案是使用sysctl来获取hw.memsize，如先前答案中所建议的那样.这是执行此操作的实际代码.
The answer is to use sysctl to get hw.memsize as was suggested in a previous answer. Here's the actual code for doing that.
#include <sys/types.h>
#include <sys/sysctl.h>
...
int mib[2];
int64_t physical_memory;
size_t length;
// Get the Physical memory size
mib[0] = CTL_HW;
mib[1] = HW_MEMSIZE;
length = sizeof(int64_t);
sysctl(mib, 2, &physical_memory, &length, NULL, 0);