Fix microsoft#5453 to enable handling of over 64 processors

YexuanXiao · web-flow · commit f6a5f91a54fe · 2025-05-02T09:12:08.000+08:00
[`GetActiveProcessorCount`](https://learn.microsoft.com/zh-cn/windows/win32/api/winbase/nf-winbase-getactiveprocessorcount) [Raymond Chen's claim](https://devblogs.microsoft.com/oldnewthing/20200824-00/?p=104116)
diff --git a/stl/src/cthread.cpp b/stl/src/cthread.cpp
@@ -103,9 +103,7 @@ _CRTIMP2_PURE _Thrd_id_t __cdecl _Thrd_id() noexcept { // return unique id for c
 }
 
 _CRTIMP2_PURE unsigned int __cdecl _Thrd_hardware_concurrency() noexcept { // return number of processors
-    SYSTEM_INFO info;
-    GetNativeSystemInfo(&info);
-    return info.dwNumberOfProcessors;
+    return GetActiveProcessorCount(ALL_PROCESSOR_GROUPS);
 }
 
 // TRANSITION, ABI: _Thrd_create() is preserved for binary compatibility

Original file line number	Diff line number	Diff line change
`@@ -103,9 +103,7 @@ _CRTIMP2_PURE _Thrd_id_t __cdecl _Thrd_id() noexcept { // return unique id for c`
`103`	`103`	`}`
`104`	`104`
`105`	`105`	`_CRTIMP2_PURE unsigned int __cdecl _Thrd_hardware_concurrency() noexcept { // return number of processors`
`106`		`- SYSTEM_INFO info;`
`107`		`- GetNativeSystemInfo(&info);`
`108`		`- return info.dwNumberOfProcessors;`
	`106`	`+ return GetActiveProcessorCount(ALL_PROCESSOR_GROUPS);`
`109`	`107`	`}`
`110`	`108`
`111`	`109`	`// TRANSITION, ABI: _Thrd_create() is preserved for binary compatibility`