Number of logical CPUs and CPU cores obtained under Windows (with GetLogicalProcessorInformation, API starting from XP3)

Code can run correctly under Windows NT

Please refer to the following documentation for specific API descriptions:

GetLogicalProcessorInformation

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2. typedef BOOL (WINAPI *lpfn_glpi) (psystem_logical_processor_information, Pdword);
6. DWORD countsetbits (ULONG_PTR bitmask)
8. {
10. DWORD lshift = sizeof (ULONG_PTR) *8-1;
12. DWORD bitsetcount = 0;
14. Ulong_ptr bittest = (ulong_ptr) 1 << LShift;
16. DWORD i;
20. for (i = 0; I <= lshift; ++i)
22. {
24. Bitsetcount + = ((Bitmask & Bittest) 1:0);
26. bittest/=2;
28. }
32. return bitsetcount;
34. }
36. Lpfn_glpi GLPI;
38. Glpi = (LPFN_GLPI) GetProcAddress (GetModuleHandle (TEXT ("kernel32")), "getlogicalprocessorinformation");
40. if (NULL = = Glpi)
42. {
44. printf ("GetLogicalProcessorInformation is not supported.\n");
46. }
48. BOOL Done = FALSE;
50. Psystem_logical_processor_information buffer = NULL;
52. Psystem_logical_processor_information ptr = NULL;
54. DWORD returnlength = 0;
56. while (!done)
58. {
60. DWORD rc = glpi (buffer, &returnlength);
64. if (FALSE = = RC)
66. {
68. if (GetLastError () = = Error_insufficient_buffer)
70. {
72. if (buffer)
74. Free (buffer);
78. buffer = (psystem_logical_processor_information) malloc (returnlength);
82. if (NULL = = buffer)
84. {
86. printf ("Error:allocation failure\n");
88. return (2);
90. }
92. }
94. Else
96. {
98. printf ("Error%d\n", GetLastError ());
100. return (3);
102. }
104. }
106. Else
108. {
110. Done = TRUE;
112. }
114. }
118. ptr = buffer;
120. DWORD byteoffset = 0;
122. DWORD logicalprocessorcount = 0;
124. DWORD processorcorecount = 0;
128. while (Byteoffset + sizeof (system_logical_processor_information) <= returnlength)
130. {
132. Switch (ptr->relationship)
134. {
136. Case Relationprocessorcore:
138. processorcorecount++;
140. Logicalprocessorcount + = countsetbits (ptr->processormask);
142. Break
144. }
146. Byteoffset + = sizeof (system_logical_processor_information);
148. ptr++;
150. }
152. printf ("logical:%d core:%d\n", Logicalprocessorcount, Processorcorecount);

http://blog.csdn.net/tobacco5648/article/details/22201169

Number of logical CPUs and CPU cores obtained under Windows (with GetLogicalProcessorInformation, API starting from XP3)