From: LIU Hao <lh_mouse@126.com>
Date: Sat, 1 Oct 2022 16:57:08 +0000 (+0800)
Subject: libstdc++/thread: Implement `_GLIBCXX_NPROCS` for Windows
X-Git-Tag: basepoints/gcc-14~3824
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=47684e58edc92ffdd4c636dbd34359b4c22e863a;p=thirdparty%2Fgcc.git

libstdc++/thread: Implement `_GLIBCXX_NPROCS` for Windows

This makes `std::thread::hardware_concurrency()` return the number of
logical processors, instead of zero.

libstdc++-v3/ChangeLog:
	* src/c++11/thread.cc (get_nprocs): Add new implementation
	for native Windows targets
---

diff --git a/libstdc++-v3/src/c++11/thread.cc b/libstdc++-v3/src/c++11/thread.cc
index 707a4ad415b9..a54bc3e939a0 100644
--- a/libstdc++-v3/src/c++11/thread.cc
+++ b/libstdc++-v3/src/c++11/thread.cc
@@ -68,6 +68,15 @@ static inline int get_nprocs()
 #elif defined(_GLIBCXX_USE_SC_NPROC_ONLN)
 # include <unistd.h>
 # define _GLIBCXX_NPROCS sysconf(_SC_NPROC_ONLN)
+#elif defined(_WIN32)
+# include <windows.h>
+static inline int get_nprocs()
+{
+  SYSTEM_INFO sysinfo;
+  GetSystemInfo(&sysinfo);
+  return (int) sysinfo.dwNumberOfProcessors;
+}
+# define _GLIBCXX_NPROCS get_nprocs()
 #else
 # define _GLIBCXX_NPROCS 0
 #endif