Linux函数整理 sysconf

Posted 2020-08-01

sysconf这个函数用来获取系统执行的配置信息。例如页大小、最大页数、cpu个数、打开句柄的最大个数等。

 

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

#define ONE_MB (1024 * 1024)

int main()
{
　　//处理器数目
    printf("The number of processors configured is :%ld\n",
        sysconf(_SC_NPROCESSORS_CONF));
    printf("The number of processors currently online (available) is :%ld\n",
        sysconf(_SC_NPROCESSORS_ONLN));
　　//页大小
    printf ("The pagesize: %ld\n", sysconf(_SC_PAGESIZE));  
　　//页数目
    printf ("The number of pages: %ld\n", sysconf(_SC_PHYS_PAGES));  
    printf ("The number of available pages: %ld\n", sysconf(_SC_AVPHYS_PAGES)); 
　　//内存
    printf ("The memory size: %lld MB\n", 
        (long long)sysconf(_SC_PAGESIZE) * (long long)sysconf(_SC_PHYS_PAGES) / ONE_MB ); 
　　//最大打开文件数 
    printf ("The number of files max opened:: %ld\n", sysconf(_SC_OPEN_MAX));  
　　//时钟
    printf("The number of ticks per second: %ld\n", sysconf(_SC_CLK_TCK));  
    printf ("The max length of host name: %ld\n", sysconf(_SC_HOST_NAME_MAX));  
    printf ("The max length of login name: %ld\n", sysconf(_SC_LOGIN_NAME_MAX)); 
    return 0;
}