Getting the CPU count

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文章标签：

#fp #osx #file #2010 #string #api

本文介绍了一种通过读取/proc/cpuinfo文件来获取Linux系统中CPU核心数量的方法，并提供了一个简洁的C++实现示例。

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I managed to put this together, but I really don't like it. Is there possibly a more straightforward way to do this?

#include <iostream> #include "stdio.h" using namespace std; int main(){ FILE * fp; char res[128]; fp = popen("/bin/cat /proc/cpuinfo |grep -c '^processor'","r"); fread(res, 1, sizeof(res)-1, fp); fclose(fp); cout << "number of core: " << res[0] << endl; return 0; }

//LInux get cpu count

ushort getCPUcount(){
    std::ifstream cpuinfo("/proc/cpuinfo"

);
    std::string line;
    /*
    I read somewhere that the processor ID could be repeated. I don't know if
    that's true or not.
    */


    std::set<unsigned

> IDs;
    while

 (!cpuinfo.eof()){
        std::getline(cpuinfo,line);
        if

 (!line.size())
            continue

;
        if

 (line.find("processor"

)!=0)
            continue

;
        size_t start=line.find(':'

),
            end;
        for

 (;line[start]<'0'

 || line[start]>'9'

;start++);
        for

 (end=start;line[end]>='0'

 && line[end]<='9'

;end++);
        line=line.substr(start,end-start);
        IDs.insert(atoi(line.c_str()));
    }
    return

 IDs.size();
}

Last edited on Dec 23, 2008 at 2:11amOct 15, 2010 at 6:26am UTC

engin (1) Dec 26, 2008 at 1:51pmOct 15, 2010 at 6:26am UTC

#include <iostream>


#include "stdio.h"



using

 namespace

 std;

int

 main(){
        FILE * fp;
        char

 res[128];
        fp = popen("/bin/cat /proc/cpuinfo |grep -c '^processor'"

,"r"

);
        fread(res, 1, sizeof

(res)-1, fp);
        fclose(fp);
        cout << "number of core: "

 << res[0] << endl;
        return

 0;
}

good luck :)

helios (7842)	Dec 26, 2008 at 2:27pmOct 15, 2010 at 6:26am UTC
Well, it is shorter. It's not exactly what I had in mind, but at least it's elegant. Thanks.

jwoolsto (36)	Jan 10, 2009 at 11:03amOct 15, 2010 at 6:26am UTC
I don't suppose anyone would be willing to help me find that file on OSX? There is no proc directory in my root directory.

Zaita (2113)	Jan 12, 2009 at 3:22amOct 15, 2010 at 6:26am UTC
jwoolsto: That's an OSX question, it'll be either an API call or stored in a file on your file system.

jwoolsto (36)	Jan 12, 2009 at 4:28amOct 15, 2010 at 6:26am UTC
Zaita: I posted on an osx forum as well, but I figured the odds were decent at least I wasn't the only one here programming on osx so I thought it was worth a shot.