linux C++ 不延时获取CPU占用率

在Linux系统中，可以通过读取/proc/stat文件来获取CPU的使用情况，并计算出CPU的占用率。以下是一个不需要延时获取CPU占用率的C++代码示例：

#include <iostream>
#include <fstream>
#include <sstream>
#include <stdlib.h>
#include <unistd.h>

using namespace std;

double GetCPULoad()
{
    ifstream proc_stat("/proc/stat");
    string line;
    getline(proc_stat, line);
    istringstream iss(line);
    string cpu;
    long long user, nice, sys, idle, iowait, irq, softirq, steal, guest, guest_nice;
    iss >> cpu >> user >> nice >> sys >> idle >> iowait >> irq >> softirq >> steal >> guest >> guest_nice;
    long long Idle = idle + iowait;
    long long NonIdle = user + nice + sys + irq + softirq + steal;
    long long Total = Idle + NonIdle;

    // calculate CPU usage percentage
    double CPU_Percentage = (double)(Total - Idle) / (double)Total;
    return CPU_Percentage;
}

int main()
{
    while (true) {
        cout << "CPU usage: " << GetCPULoad() * 100 << "%" << endl;
        usleep(1000000); // sleep for 1 second
    }
    return 0;
}

该代码会每秒钟输出一次CPU使用率。使用usleep函数实现在不延时的情况下获取CPU占用率。你可以根据需要修改输出内容和时间间隔。