ubuntu下C/C++獲取剩餘內存

#include <stdio.h>
#include <unistd.h>
long get_memory_usage()
{
    long page_size = sysconf (_SC_PAGESIZE);
    long num_pages = sysconf (_SC_PHYS_PAGES);
    long mem = (num_pages/1024) * (page_size/1024);
    long long free_pages = sysconf (_SC_AVPHYS_PAGES);
    long long free_mem = (free_pages/1024) * (page_size/1024);
    fprintf(stderr,"Memory %lld MB\\%lld MB.\n", mem, free_mem);
    return (long)(free_mem);
}

獲取結果與System Monitor中的不一致，不過內存管夠的狀況下通常在150~200MB之間波動，重啓閾值設在100MB能夠湊合用

 

另外一方法

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
long get_memory_usage()
{
    FILE*file=fopen("/proc/meminfo","r");
    if(file == NULL){
        fprintf(stderr,"cannot open /proc/meminfo\n");
        return 1024;
    }
    char keyword[20];
    char valuech[20];
    long mem        =0;
    long free_mem   =0;
    fscanf(file,"MemTotal: %s kB\n",keyword);
    mem=atol(keyword)/1000;
    fscanf(file,"MemFree: %s kB\n",valuech);
    fscanf(file,"MemAvailable: %s kB\n",valuech);
    free_mem=atol(valuech)/1000;
    fclose(file);
    fprintf(stderr,"Memory %ld MB\\%ld MB.\n", mem, free_mem);
    return (long)(free_mem);
}

與在GUI中可見的剩餘內存相同，推薦做爲參考方法