有没有一种简便的方法来获取Linux中当前的进程数? [英] Is there a lightweight way to obtain the current number of Processes in Linux?

问题描述

我希望我的(基于C/C ++)程序显示一个数字指示器，该指示器指示本地系统上当前存在多少个进程.经常会查询运行次数的值(例如每秒一次)以更新我的显示.

是否有一种简便的方法来获取该号码?显然，我可以称其为"ps ax | wc -l"，但我不希望强迫计算机产生一个进程并解析几百行文本，以得出一个整数.

该程序主要在Linux下运行，但也可能在MacOS/X或Windows下运行，因此与这些OS相关的技术也将有所帮助.

理想情况下，我正在寻找类似此，但在Linux下可用(getsysinfo()似乎更像是Minix的东西).

解决方案

....当然，在我发布问题1分钟后，我便找到了答案:sysinfo 将返回(除其他外)一个表明有多少进程的字段.

也就是说，如果有人知道与sysinfo()等效的MacOS/X和/或Windows，我仍然对此感兴趣.

---

更新:这是我最终得到的功能.

  #ifdef __linux__#include< sys/sysinfo.h>#elif已定义(__APPLE__)#include< sys/sysctl.h>#elif定义(WIN32)#include< Psapi.h>#万一int GetTotalNumProcesses(){#如果已定义(__linux__)struct sysinfo si;返回(sysinfo(& si)== 0)吗?(int)si.procs:(int)-1;#elif已定义(__APPLE__)size_t长度= 0;静态const int名称[] = {CTL_KERN，KERN_PROC，KERN_PROC_ALL，0};返回(sysctl((int *)names，(((sizeof(names)/sizeof(names [0]))-1，NULL，& length，NULL，0)== 0)?(int)(length/sizeof(kinfo_proc)):(int)-1;#elif定义(WIN32)DWORD aProcesses [1024]，cbNeeded；返回EnumProcesses(aProcesses，sizeof(aProcesses)，& cbNeeded)吗?(cbNeeded/sizeof(DWORD)):-1;#别的返回-1;#万一} 

I want my (C/C++ based) program to display a numeric indicator of how many processes are currently present on the local system. The number-of-running-processes value would be queried often (e.g. once per second) to update my display.

Is there a lightweight way to get that number? Obviously I could call "ps ax | wc -l", but I'd prefer not to force the computer to spawn a process and parse several hundred lines of text just to come up with a single integer.

This program will be running primarily under Linux, but it might also run under MacOS/X or Windows also, so techniques relevant to those OS's would be helpful also.

Ideally I'm looking for something like this, except available under Linux (getsysinfo() appears to be more of a Minix thing).

解决方案

.... and of course 1 minute after I post the question, I figure out the answer: sysinfo will return (amongst other things) a field that indicates how many processes there are.

That said, if anyone knows of a MacOS/X and/or Windows equivalent to sysinfo(), I'm still interested in that.

---

Update: Here's the function I finally ended up with.

#ifdef __linux__
# include <sys/sysinfo.h>
#elif defined(__APPLE__)
# include <sys/sysctl.h>
#elif defined(WIN32)
# include <Psapi.h>
#endif

int GetTotalNumProcesses()
{
#if defined(__linux__)
   struct sysinfo si;
   return (sysinfo(&si) == 0) ? (int)si.procs : (int)-1;
#elif defined(__APPLE__)
   size_t length = 0;
   static const int names[] = {CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0};
   return (sysctl((int *)names, ((sizeof(names)/sizeof(names[0]))-1, NULL, &length, NULL, 0) == 0) ? (int)(length/sizeof(kinfo_proc)) : (int)-1;
#elif defined(WIN32)
   DWORD aProcesses[1024], cbNeeded;
   return EnumProcesses(aProcesses, sizeof(aProcesses), &cbNeeded) ? (cbNeeded/sizeof(DWORD)) : -1;
#else
   return -1;
#endif
}

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