物理メモリの使用状況を取得 - vm_statistics

例によって例の如く，無責任かつ雑なので参考程度に．
もう少しサクっと取得できないものだろうか．vm_stat をパースする以外の手法で！

vmstatistics.c

#include <stdio.h>
#include <stdlib.h>
#include <mach/mach_init.h>
#include <mach/mach_host.h>

#define MB  / 1024 / 1024.0
#define GB  MB / 1024.0

int main(int argc, char **argv)
{
  struct vm_statistics   vm_stat;
  struct host_basic_info host_info;

  host_priv_t        host_priv = mach_host_self();
  mach_msg_type_number_t count = HOST_VM_INFO_COUNT;
  kern_return_t            err = KERN_SUCCESS;

  err = host_statistics(host_priv, HOST_VM_INFO, (host_info_t)&vm_stat, &count);

  if( err != KERN_SUCCESS ) { 
    perror("host_statistics");
    exit(err);
  }

  double free_size     = (vm_stat.free_count     * vm_page_size) GB; 
  double active_size   = (vm_stat.active_count   * vm_page_size) GB; 
  double inactive_size = (vm_stat.inactive_count * vm_page_size) GB; 
  double wire_size     = (vm_stat.wire_count     * vm_page_size) GB; 

  printf("page size  ; %ld bytes\n", vm_page_size);
  printf("free       ; %lf GB\n",    free_size);
  printf("active     ; %lf GB\n",    active_size);
  printf("inactive   ; %lf GB\n",    inactive_size);
  printf("wire       ; %lf GB\n",    wire_size);
  printf("total      ; %lf GB\n",    free_size + active_size + inactive_size + wire_size);

  return 0;
}

% clang vmstatistics.c -o vmstatistics && ./vmstatistics
page size  ; 4096 bytes
free       ; 4.442173 GB
active     ; 1.930828 GB
inactive   ; 0.878677 GB
wire       ; 0.746510 GB
total      ; 7.998188 GB