【Darwin学习笔记】之获取系统处理器数量的方法

阅读Darwin源码的时候看到这个方法，感觉挺有用处，且考虑了多种平台下的实现方式，直接贴代码，以后说不定会用到~

单一种平台下的实现方法可能很容易，但是把这些个系统都收集在一起，在一个函数中实现还是极好的

【转载请注明出处】：http://blog.csdn.net/longlong530

1.  
   UInt32 OS::GetNumProcessors()
2.  
   {
3.  
   #if (__Win32__)
4.  
   SYSTEM_INFO theSystemInfo;
5.  
   ::GetSystemInfo(&theSystemInfo);
6.  
    
7.  
   return (UInt32)theSystemInfo.dwNumberOfProcessors;
8.  
   #endif
9.  
    
10.  
    #if (__MacOSX__ || __FreeBSD__)
11.  
    int numCPUs = 1;
12.  
    size_t len = sizeof(numCPUs);
13.  
    int mib[2];
14.  
    mib[0] = CTL_HW;
15.  
    mib[1] = HW_NCPU;
16.  
    (void) ::sysctl(mib,2,&numCPUs,&len,NULL,0);
17.  
    if (numCPUs < 1)
18.  
    numCPUs = 1;
19.  
    return (UInt32) numCPUs;
20.  
    #endif
21.  
     
22.  
    #if(__linux__ || __linuxppc__)
23.  
     
24.  
    char cpuBuffer[8192] = "";
25.  
    StrPtrLen cpuInfoBuf(cpuBuffer, sizeof(cpuBuffer));
26.  
    FILE *cpuFile = ::fopen( "/proc/cpuinfo", "r" );
27.  
    if (cpuFile)
28.  
    { cpuInfoBuf.Len = ::fread(cpuInfoBuf.Ptr, sizeof(char), cpuInfoBuf.Len, cpuFile);
29.  
    ::fclose(cpuFile);
30.  
    }
31.  
     
32.  
    StringParser cpuInfoFileParser(&cpuInfoBuf);
33.  
    StrPtrLen line;
34.  
    StrPtrLen word;
35.  
    UInt32 numCPUs = 0;
36.  
     
37.  
    while( cpuInfoFileParser.GetDataRemaining() != 0 )
38.  
    {
39.  
    cpuInfoFileParser.GetThruEOL(&line); // Read each line
40.  
    StringParser lineParser(&line);
41.  
    lineParser.ConsumeWhitespace(); //skip over leading whitespace
42.  
     
43.  
    if (lineParser.GetDataRemaining() == 0) // must be an empty line
44.  
    continue;
45.  
     
46.  
    lineParser.ConsumeUntilWhitespace(&word);
47.  
     
48.  
    if ( word.Equal("processor") ) // found a processor as first word in line
49.  
    { numCPUs ++;
50.  
    }
51.  
    }
52.  
     
53.  
    if (numCPUs == 0)
54.  
    numCPUs = 1;
55.  
     
56.  
    return numCPUs;
57.  
    #endif
58.  
     
59.  
    #if(__solaris__)
60.  
    {
61.  
    UInt32 numCPUs = 0;
62.  
    char linebuff[512] = "";
63.  
    StrPtrLen line(linebuff, sizeof(linebuff));
64.  
    StrPtrLen word;
65.  
     
66.  
    FILE *p = ::popen("uname -X","r");
67.  
    while((::fgets(linebuff, sizeof(linebuff -1), p)) > 0)
68.  
    {
69.  
    StringParser lineParser(&line);
70.  
    lineParser.ConsumeWhitespace(); //skip over leading whitespace
71.  
     
72.  
    if (lineParser.GetDataRemaining() == 0) // must be an empty line
73.  
    continue;
74.  
     
75.  
    lineParser.ConsumeUntilWhitespace(&word);
76.  
     
77.  
    if ( word.Equal("NumCPU")) // found a tag as first word in line
78.  
    {
79.  
    lineParser.GetThru(NULL,'=');
80.  
    lineParser.ConsumeWhitespace(); //skip over leading whitespace
81.  
    lineParser.ConsumeUntilWhitespace(&word); //read the number of cpus
82.  
    if (word.Len > 0)
83.  
    ::sscanf(word.Ptr, "%"_U32BITARG_"", &numCPUs);
84.  
     
85.  
    break;
86.  
    }
87.  
    }
88.  
    if (numCPUs == 0)
89.  
    numCPUs = 1;
90.  
     
91.  
    ::pclose(p);
92.  
     
93.  
    return numCPUs;
94.  
    }
95.  
    #endif
96.  
     
97.  
    #if(__sgi__)
98.  
    UInt32 numCPUs = 0;
99.  
     
100.  
     numCPUs = sysconf(_SC_NPROC_ONLN);
101.  
      
102.  
     return numCPUs;
103.  
     #endif
104.  
      
105.  
      
106.  
     return 1;
107.  
     }

PS:  函数摘自Darwin源码：StreamServerCommonUtilitiesLibOS.cpp