Linux sysconf函数

函数原型：

NAME
       sysconf - Get configuration information at runtime

SYNOPSIS
       #include <unistd.h>

       long sysconf(int name);

#include <stdio.h>
#include <unistd.h>

#define ONE_MB (1024 * 1024)

int main (void)
{
    long num_procs;
    long page_size;
    long num_pages;
    long free_pages;
    long long  mem;
    long long  free_mem;

    num_procs = sysconf (_SC_NPROCESSORS_CONF);
    printf ("CPU 个数为: %ld 个\n", num_procs);

    page_size = sysconf (_SC_PAGESIZE);
    printf ("系统页面的大小为: %ld K\n", page_size / 1024 );

    num_pages = sysconf (_SC_PHYS_PAGES);
    printf ("系统中物理页数个数: %ld 个\n", num_pages);

    free_pages = sysconf (_SC_AVPHYS_PAGES);
    printf ("系统中可用的页面个数为: %ld 个\n", free_pages);

    mem = (long long) ((long long)num_pages * (long long)page_size);
    mem /= ONE_MB;

    free_mem = (long long)free_pages * (long long)page_size;
    free_mem /= ONE_MB;

    printf ("总共有 %lld MB 的物理内存, 空闲的物理内存有: %lld MB\n", mem, free_mem);
    return (0);
}